12 / 02 / 2022
CHAPTER-16
What is a Triangle?
In geometry, a triangle is a closed, two-dimensional shape with three straight sides. A triangle is also a polgon.
We can find the shape of a triangle in a flag, the musical instrument triangle, and a roadside signboard.
Different Types of Triangles
To classify triangles according to their angles, we measure each of its interior angles. Triangles can be classified by angles, as:
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An acute triangle has all interior angles acute (less than 90°), a right triangle has one right angle (equal to 90°) and an obtuse triangle has one obtuse angle (greater than 90°).
To classify the triangles according to their sides, we measure the length of each of its sides. Triangles can be classified by their sides, as:
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To classify triangles according to both angles and sides, we measure the interior angles and length of the sides of the triangle.
What is Quadrilateral?
In geometry, a quadrilateral can be defined as a closed, two-dimensional shape which has four straight sides.
The polygon has four vertices or corners.
We can find the shape of quadrilaterals in various things around us, like in a chess board, a deck of cards, a kite, a tub of popcorn, a sign board and in an arrow.
Types of Quadrilaterals
Quadrilaterals can be classified into Parallelograms, Squares, Rectangles and Rhombuses. Square, Rectangle and Rhombus are also Parallelograms.
Here's a list of the types of quadrilaterals with their name, pictures and properties:
ASSIGNMENTS
Revise Chapter-16 and learn the definitions.
11 / 02 / 2022
FORMATIVE ASSESSMENT-4
ASSIGNMENTS
Revise Chapter-16.
09 / 02 / 2022, 10 / 02 / 2022
CHAPTER:-15 POINTS, LINES, RAYS AND SEGMENTS
REVISION
ASSIGNMENTS
Revise Ch-14 and 15 all ex's for FA-4 (11/02/2022).
08 / 02 / 2022
REVISION OF CHAPTER-14 CALENDAR
Page nos:- 154-156
ASSIGNMENTS
Revise Ch-14 all exercises.
07 / 02 / 2022
Time is the ongoing sequence of events taking place. The past, present and future.
The basic unit of time is the second. There are also minutes, hours, days, weeks, months and years.
We can measure time using clocks.
There are two main ways to show the time: "24 Hour Clock" or "AM/PM":
24 Hour Clock: the time is shown as how many hours and minutes since midnight.
AM/PM (or "12 Hour Clock"): the day is split into:
- the 12 Hours running from Midnight to Noon (the AM hours), and
- the other 12 Hours running from Noon to Midnight (the PM hours).
Converting AM/PM to 24 Hour ClockAdd 12 to any hour after Noon (and subtract 12 for the first hour of the day):For the first hour of the day (12 Midnight to 12:59 AM), subtract 12 HoursExamples: 12 Midnight = 00:00, 12:35 AM = 00:35From 1:00 AM to 12:59 PM, no changeExamples: 11:20 AM = 11:20, 12:30 PM = 12:30From 1:00 PM to 11:59 PM, add 12 HoursExamples: 4:45 PM = 16:45, 11:50 PM = 23:50
Converting 24 Hour Clock to AM/PMFor the first hour of the day (00:00 to 00:59), add 12 Hours, make it "AM"Examples: 00:10 = 12:10 AM, 00:40 = 12:40 AMFrom 01:00 to 11:59, just make it "AM"Examples: 01:15 = 1:15 AM, 11:25 = 11:25 AMFrom 12:00 to 12:59, just make it "PM"Examples: 12:10 = 12:10 PM, 12:55 = 12:55 PMFrom 13:00 to 23:59, subtract 12 Hours, make it "PM"Examples: 14:55 = 2:55 PM, 23:30 = 11:30 PM
Add 12 to any hour after Noon (and subtract 12 for the first hour of the day):
For the first hour of the day (12 Midnight to 12:59 AM), subtract 12 Hours
Examples: 12 Midnight = 00:00, 12:35 AM = 00:35
From 1:00 AM to 12:59 PM, no change
Examples: 11:20 AM = 11:20, 12:30 PM = 12:30
From 1:00 PM to 11:59 PM, add 12 Hours
Examples: 4:45 PM = 16:45, 11:50 PM = 23:50
Converting 24 Hour Clock to AM/PM
For the first hour of the day (00:00 to 00:59), add 12 Hours, make it "AM"
Examples: 00:10 = 12:10 AM, 00:40 = 12:40 AM
From 01:00 to 11:59, just make it "AM"
Examples: 01:15 = 1:15 AM, 11:25 = 11:25 AM
From 12:00 to 12:59, just make it "PM"
Examples: 12:10 = 12:10 PM, 12:55 = 12:55 PM
From 13:00 to 23:59, subtract 12 Hours, make it "PM"
Examples: 14:55 = 2:55 PM, 23:30 = 11:30 PM
TimeAdd or Subtract the hours and minutes separately.But you may need to do some adjusting if the minutes end up 60 or more, or less than zero!
Adding TimesFollow these steps:
Time
Add or Subtract the hours and minutes separately.
But you may need to do some adjusting if the minutes end up 60 or more, or less than zero!
Adding Times
Follow these steps:
- Add the hours
- Add the minutes
- If the minutes are 60 or more, subtract 60 from the minutes and add 1 to hours
Like this:
Easy example: What is 2:45 + 1:10 ?
Add the Hours: 2+1 = 3
Add the Minutes: 45+10 = 55
The minutes are OK, so the answer is 3:55
Hard example: What is 2:45 + 1:20 ?
Add the Hours: 2+1 = 3
Add the Minutes: 45+20 = 65
The minutes are 60 or more, so
- subtract 60 from minutes (65−60 = 5 Minutes)
- and add 1 to Hours (3+1 = 4 Hours)
The answer is 4:05
Subtracting Times
Follow these steps:
- Subtract the hours
- Subtract the minutes
- If the minutes are negative, add 60 to the minutes and subtract 1 from hours.
Like this:
Easy example: What is 4:10 - 1:05 ?
Subtract the Hours: 4−1 = 3
Subtract the Minutes: 10−5 = 5
The minutes are OK, so the answer is 3:05
Hard example: What is 4:10 - 1:35 ?
Subtract the Hours: 4−1 = 3
Subtract the Minutes: 10−35 = −25
The minutes are less than 0, so:
- add 60 to Minutes (−25+60 = 60−25 = 35 Minutes)
- and subtract 1 from Hours (3−1 = 2 Hours)
The answer is 2:35
ASSIGNMENTS
Revise Chapter-13 all exercises.
31 / 01 / 2022
In metric system of measurement the metre is the basic unit of length, gram is the basic unit of mass and litre is the basic unit of capacity.
In units of measurement of length we use centimeter (cm) to measure. We can use this unit for measuring the length of a pencil, the width of a book etc. but this unit is too big to measure the thicken of a pencil. So we use another unit called millimeter (mm).
Also, centimeter and millimeters are very small units to measure the length of the classroom. We use another unit called meters. Even meter is too small unit when we state the distances between two cities, there we need kilometers (km).
These units are connected with each other by the following relation :
1 kilometer (km) = 1000 meter (m)
1 meter (m) = 100 centimeter (cm)
1 centimeter (cm) = 10 millimeter (mm).
Also,
1 meter (m) = 100 centimeter (cm) = 100 × 10 millimeter (mm) = 1000 millimeter (mm)
1 kilometer (km) = 1000 meter (m) = 1000 × 100 centimeter (cm) = 100,000 centimeter (cm)
1 kilometer (km) = 100,000 centimeter (cm) = 100,000 × 10 millimeter (mm) = 1,000,000 millimeter (mm)
When we go to market to buy sugar, wheat etc, we buy these items in kilograms (kg).
But, items like ginger, chilies etc. are measured in grams (gm).
In order to measure the weight of compound or chemicals in medicines, we use smaller unit called milligrams (mg).
Following are the relations between these three units of measurement of weight.
1 kilograms (kg) = 1000 grams (gm)
1 grams (gm) = 1000 milligrams (mg)
1 kilograms (kg) = 1000 × 1000 milligrams (mg) = 1,000,000 milligrams (mg)
We buy milk in liters whereas liquid medicines etc. are measured in milliliters (ml).
Following is the relation between these two units.
1 liter (l) = 1000 milliliters (ml).
Following prefixes are used to understand easily the relationship between higher units and lower units.
Kilo – thousand, hector – hundred, deca – ten, deci – tenth, centi – hundredth and milli – thousandth
We can write the place-value chart using all above prefixes for each place explaining the relationship to the basic unit. In the following place-value chart each place is ten times greater than the one to its right, and ten times smaller than the one to its left.
We shall express measures now using the decimal rotation.
Note:
In units of measurement, all the units mentioned above have some common words like kilo, milli and centi. It should be noted that kilo is the largest and milli is the smallest. Similarly, centi shows 100 times smaller.
ASSIGNMENTS
Revise Chapter-12 all exercises.
24 / 01 / 2022
ASSIGNMENTS
Revise Chapter-11, Exercise-A full.
19 / 01 / 2022
Chapter-20 Pictorial Representation of DataPictorial Representation of Data
When we represent numerical data through pictures or graph, it is termed as more clear.
In pictograph we use icon, pictures, symbol etc. repetitively, to show the relationship between two variable quantities. Pictograph can also be referred as pictogram, pictorial chart, pictorial graph, or picture graph. The quantity that each symbol or picture symbolizes is specified clearly in the representation, this helps to represent large quantities of data.
Example: The below graph shows how many oranges were sold in 3 weeks
Now, answer the following questions:
Q1. How many oranges were sold during the third Week?
Ans. 20 x 3 = 60 oranges (as each orange stand for 20 oranges)
Q2. In which Week the oranges sold were maximum?
Ans. In Week 2
Chapter-21 Roman Numerals
ASSIGNMENTS
Revise Chapters (20 and 21) full.
17 / 01 / 2022
Page nos:-181-183
Do Exercise-21A full , page-183 in ex-bk.
12 / 01 / 2022
A Pictograph is a way of showing data using images.
Each image stands for a certain number of things.
Example: Apples Sold
Here is a pictograph of how many apples were sold at the local shop over 4 months:
Note that each picture of an apple means 10 apples (and the half-apple picture means 5 apples).
So the pictograph is showing:
- In January 10 apples were sold
- In February 40 apples were sold
- In March 25 apples were sold
- In April 20 apples were sold
We can also draw a picture graph for a given set of data.
Here, is the data showing the number of children who visited a library during the first three months of a year.
| Library Visit | |
| Month | Number of children |
| January | 40 |
| February | 35 |
| March | 50 |
To represent this data on a pictograph, follow the given steps:
- Think of a picture or a symbol to represent the children.
- Then, decide on a suitable scale to represent the number of children. For a scale of 10, each symbol or picture would represent 10 children.
Mention the key (the scale used).
So, taking a scale of 10, we get the picture graph as:
Now watch the video given on date 10/01/2022.
ASSIGNMENTS
Do Exercise-20A ,Nos 6-10 page nos179-180 in text-book.
Do Exercise-20A ,Nos 6-10 page nos179-180 in text-book.
10 / 01 / 2022
( Download Ch-20 in pdf by clicking on the chapter's name above. )
Page nos:-176-178
Now let's watch the video to help you understand better.
ASSIGNMENTS
Do Exercise-20A ,Nos 1-5 page nos 178-179 in text-book.
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22 / 12 / 2021
(Download Ch-19 in pdf by clicking on the chapter's name above.)
Page nos:-171-174
Now let's watch the video to help you understand better.
ASSIGNMENTS
Do Exercise-19B, Nos 9 - 32 page nos 174-175 in ex-bk.
08 / 12 / 2021
Ch-13 MEASURES TO TIME
ASSIGNMENTS
Revise Chapter-13 all ex's for Formative Assessment-III.
06 / 12 / 2021
Ch-11 UNITARY METHOD
CH-12 MEASURES OF LENGTH,MASS AND CAPACITY
ASSIGNMENTS
Revise Chapter-11 and 12 all ex's for Formative Assessment-III.
01 / 12 / 2021
(Download Ch-19 in pdf by clicking on the chapter's name above.)
Page nos:-171-174
Page nos:-171-174
Perimeter of a Rectangle
A rectangle is a closed figure that has equal opposite sides and each angle is of 90 degree. The longer side of rectangle is known as length of the rectangle and shorter side is known as width or breadth of rectangle.
Perimeter of Rectangle
= L + L + B + B
OR
=2 X L + 2 X B (i.e. 2L + 2B)
OR
=2 (L + B) (taking 2 common i.e. twice the sum of length and breadth)
Example: Length =10cm and Breadth = 5cm
Method 1: Perimeter = 10 + 10 + 5 + 5 (sum of all 4 sides)
= 30 cm
Method 2: As opposite sides are equal we can write sum 2 times length and 2 times breadth.
Perimeter = 2 X L + 2 X B (i.e. 2L + 2B)
= 2 x 10 + 2 x 5
= 20 + 10
= 30 cm
OR
Perimeter = 2 (L + B)
= 2 (10 + 5) (solve bracket first)
= 2 X 15
= 30 cm
Now let's watch the video to help you understand better.
Video-1 Perimeter
Video-1 Perimeter
ASSIGNMENTS
Do Exercise-19A full and Exercise-19B, Nos 1-8 page-174 in ex-bk.
29 / 11 / 2021
Chapter-18 Symmetry of Shapes
Page nos:- 169-170
Page nos:- 169-170
Now let's watch the video to help you understand better.
ASSIGNMENTS
Do Exercise-18A full, page nos:- 170 in ex-bk.
24 / 11 / 2021
Chapter-17 Circle
Page nos:-167-168
Now let's watch the video to help you understand better.
ASSIGNMENTS
Do Exercise-17A full, page no-168 in ex-bk.
22 / 11 / 2021
(Download Ch-16 in pdf by clicking on the chapter's name above.)
Page nos:-164-166
Now let's watch the videos to help you understand better.
ASSIGNMENTS
Do Exercise-16A full , page no-166 in ex-bk.
17 / 11 / 2021
(Download Ch-15 in pdf by clicking on the chapter's name above.)
Page nos :-160-162
Now let's watch the videos to help you understand better.
ASSIGNMENTS
Do Exercise-15A full, page no-163 in ex-bk.
03 / 11 / 2021
Chapter-14 Calendar
Page no :-157-158
Now let's watch the video to help you understand better.
ASSIGNMENTS
Do Exercise-14A, Nos 11-18, page no:-159 in ex-bk.
01 / 11 / 2021
(Download Ch-14 in pdf by clicking on the chapter's name above.)
Page nos:- 154-156
Now let's watch the videos to help you understand better.
ASSIGNMENTS
Do Exercise-14A, Nos 1-10, page nos 158-159 in ex-bk.
27 / 10 / 2021
Ch-13 Measure of Time
Page nos:- 148-153
Ch-13 Measure of Time
Page nos:- 148-153
Time - Addition and Subtraction
Addition and Subtraction
Step1: Write the units on the top.
Step2: Write the numbers in proper place below the units. Write zero in empty place.
Step3: Now add or subtract as per the instruction given in question.
Example 1: Add 3 hrs 35 min 50 sec and 2 hrs 40 min 34 sec
Step1: Write the units on the top.
Step2: Write the numbers in proper place below the units. Write zero in empty place.
Step3: Now add or subtract as per the instruction given in question.
Example 1: Add 3 hrs 35 min 50 sec and 2 hrs 40 min 34 sec
5 hrs 75 min 84 sec = 5 hrs (60 + 15) min (60 + 24) sec
= (5 + 1) hrs (15 + 1) min 24 sec
= 6hrs 16min 24sec
= 6hrs 16min 24sec
Explanation
Step 1: As 60 sec = 1 min, so, 60 sec i.e. 1 min is carried to minutes column and 24 sec are left in seconds column. Now, we have 75 + 1 = 76 min.
Step 2: As 60 min = 1 hr. so, 60 min i.e. 1 hr is carried over to hour column and 76 – 60 = 16 are left in min column. Now, we have 5 + 1 = 6 hr.
Example 2: Subtract 3hrs 45 min 30 sec from 8 hrs 35 min 20 sec
Explanation
Step 1: As in seconds column 20 is smaller than 30, we cannot subtract 30 from 20. So, 1 min is borrowed from the minute column and we are left with 34 minutes in minute column.
Now, 1 min = 60 sec, this means 60 sec + 20 sec = 80 sec
We have 80 sec and we can subtract 30 sec from 80 sec.
80 sec – 30 sec = 50 sec
We have 80 sec and we can subtract 30 sec from 80 sec.
80 sec – 30 sec = 50 sec
Step 2: As in minutes column 34 is smaller than 45, we cannot subtract 45 from 34. So, 1 hr is borrowed from the hours column and we are left with 7 hrs in hours column.
Now, 1 hour = 60 min, this means 60 min + 34 min = 94 min
We have 94 min and we can subtract 45 min from 94 min.
94 min – 45 min = 49 min
We have 94 min and we can subtract 45 min from 94 min.
94 min – 45 min = 49 min
Step 3: Now subtract 3 hrs from 7 hrs i.e. 7 – 3 = 4hrs
Now let's watch the video to help you understand better.
ASSIGNMENTS
Do Chapter-13, Exercises D and E full.
25 / 10 / 2021
Ch-13 Measure of Time
Page nos:- 142-147
Time - Conversion
Important Points
1 hour = 60 minutes
1 minute = 60 seconds
1 hour = 60 x 60 = 3600 seconds
1 day = 24 hours
1 hour = 60 minutes
1 minute = 60 seconds
1 hour = 60 x 60 = 3600 seconds
1 day = 24 hours
We always multiply when we change higher unit to lower unit.
We always divide when we change lower unit to higher unit.
Conversion of Hours into Minutes
Example 1: Convert 2 hrs 40 min into minutes
1 hr = 60 min
Therefore, 2 hrs = 2 x 60 = 120 min
2 hrs 40 min = 120 min + 40 min = 160 minutes
Therefore, 2 hrs = 2 x 60 = 120 min
2 hrs 40 min = 120 min + 40 min = 160 minutes
Conversion of Minutes into Hours
Example 1: Convert 180 minutes into hours
60 min = 1 hour
Therefore, 180 min = 180 ÷ 60 = 3 hours
60 min = 1 hour
Therefore, 180 min = 180 ÷ 60 = 3 hours
Conversion of Minutes into Seconds
Example 1: Convert 5 min 37 sec into seconds
1 min = 60 sec
Therefore, 5 min = 5 x 60 = 300 sec
5 min 37 sec = 300 sec + 37 sec = 337 seconds
1 min = 60 sec
Therefore, 5 min = 5 x 60 = 300 sec
5 min 37 sec = 300 sec + 37 sec = 337 seconds
Conversion of Seconds into Minutes
Example 1: Convert 240 seconds into minutes
60 seconds = 1 minute
Therefore, 240 seconds = 240 ÷ 60 = 4 minutes
60 seconds = 1 minute
Therefore, 240 seconds = 240 ÷ 60 = 4 minutes
Conversion of Days into Hours
Example 1: Convert 5 days 10 hrs into hours
1 day = 24 hours
Therefore, 5 days = 5 x 24 = 120 hours
5 days 10 hrs = 120 + 10 = 130 hours
1 day = 24 hours
Therefore, 5 days = 5 x 24 = 120 hours
5 days 10 hrs = 120 + 10 = 130 hours
Conversion of Hours into Days
Example 1: Convert 145 hrs into days and hours
24 hours = 1 day
Therefore, 145 hrs = 145 ÷ 24 hours
24 hours = 1 day
Therefore, 145 hrs = 145 ÷ 24 hours
The 24 Hours Clock Time
Digital watches show time in 24 hours clock time. In case of 24-hour clock, the day runs from midnight to midnight and is divided into 24 hours, which shows the hours passed since midnight, from 0 to 23. In 24 hours clock time is shown in 4 digits.
12 o’clock midnight is expressed as 0000 hrs. and 12 o’clock noon is expressed as 1200 hrs.
Converting 24 hours clock time to 12 hours clock time.
In this case use a.m. if number of hours is less than 12 and if numbers of hours is more than 12 then subtract 12 from the number of hours given and use p.m.
Example 1: 0400 hrs.
Here, number of hours is less than 12. So, time according to 12 hours clock time is 4:00 a.m.
Example 2: 1640 hrs.
Here, number of hours is more than 12. So, we will subtract 12 from 16 hours and add p.m.
Time according to 12 hours clock time is (16 – 12 = 4) hrs. = 4:40 p.m.
A.M and P.M / 12 Hour Clock
Most of the clocks that we see are 12-hour clock. In 12 hour clock, a full day (i.e. 24 hours) are divided into two parts of 12 hour each. The first part is known as a.m. or A.M. (ante meridian), which means before noon {i.e. time between midnight (0:00) & noon (12:00)} and second part is known as p.m. or P.M. (post meridian), which means after noon {i.e. time between noon (12:00) & midnight (0:00)}.
Technically, midnight and noon, each hour of the day is suffixed by am or pm to identify whether the hour is being referred is the morning, afternoon or evening. But most digital clocks show 12 am and 12 pm to specify midnight and noon, respectively.
We generally use 12 hours clock time in which hour hand takes two round of the face of the clock in 24 hours.
Converting 12 hours clock time to 24 hours clock time.
If the time given is before 1 p.m., simply write the hours and minutes in the 24 hours clock time format. Beyond 1 p.m. add 12 to the hour part of the given time.
Example 1: 5:25 a.m.
Here time is before 1 p.m. So, we will simply write the time in 24 hours clock time format i.e. 0525 hrs.
Example 2: 6:10 p.m.
Here time is beyond 1 p.m. So, we will add 12 to the hour part of the given time.
(6 + 12 = 18) hrs.
1810 hrs.
Here time is before 1 p.m. So, we will simply write the time in 24 hours clock time format i.e. 0525 hrs.
Example 2: 6:10 p.m.
Here time is beyond 1 p.m. So, we will add 12 to the hour part of the given time.
(6 + 12 = 18) hrs.
1810 hrs.
Now let's watch the videos to help you understand better.
ASSIGNMENTS
Do Chapter-13, Exercises B and C full.
20 / 10 / 2021
Chapter-13 Measure of Time
( Download Ch-13 in pdf by clicking on the chapter's name above.)
Chapter-13 Measure of Time
( Download Ch-13 in pdf by clicking on the chapter's name above.)
Page nos:- 138-140
What is time?
In math, time can be defined as the ongoing and continuous sequence of events that occur in succession, from the past through the present to the future.
Time is a used to quantify, measure or compare the duration of events or the intervals between them, and even, sequence events.
Here, a child’s daily routine events have been put in sequence according to the time at which they are done.
We measure time in seconds, minutes, hours, days, weeks, months and years with clocks and calendars.
A day has 24 hours. We use A.M. to tell time running from midnight to noon and P.M. for time running from noon to midnight.
The hour hand, the shorter of the two hands, completes 1 rotation ( 360° ) in 12 hours in a normal 12-hour analogue. The minute hand, the longer hand, completes 1 rotation through 360° in 60 minutes.
Here’s how the minute hand’s movement shows different time in an hour.
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Fun
Facts
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Now let's watch the videos to help you understand better.
ASSIGNMENTS
Do Chapter-13, Exercise-A full in ex-bk.
18 / 10 / 2021
Ch-12 Measures of Length, Mass and Capacity
Page nos:-129-136
Metric Measure of Weight
Measurement of the heaviness of a person or thing is called weight. The standard unit of weight is kilogram. We commonly use grams and kilograms to measure weight. Milligram, centigram, decigram are smaller unit used to measure lighter things, gram is the basic unit of weight, whereas units like decagram, hectogram and kilogram are used to measure heavier things. All these units are related to each other.
When we move from one metric unit to another to the right in the above metric chart, the value of metric unit becomes ten times smaller i.e. one tenth and when we move from one metric unit to another to the left in the metric chart, the value of metric unit becomes ten times bigger.
We consider gram as the basic unit of weight.
1 Decagram (dag) = 10 times gram
1 Hectogram (hg) = 100 times gram
1 Kilogram (kg) = 1000 times gram
1 Decigram (dg) = 1/10 of gram
1 centigram (cg) = 1/100 of gram
1 milligram (mg) = 1/1000 of gram
1 Hectogram (hg) = 100 times gram
1 Kilogram (kg) = 1000 times gram
1 Decigram (dg) = 1/10 of gram
1 centigram (cg) = 1/100 of gram
1 milligram (mg) = 1/1000 of gram
Conversion of measures from higher to lower units
We always multiply when we change higher unit to lower unit.
Example 1: Change 9kg into grams
1kg =1000g
Therefore, 9 x 1000g = 9000g
Example 2: Change 5g into centigrams
1g = 100cg
Therefore, 5 x 100cg = 500cg
Therefore, 9 x 1000g = 9000g
Example 2: Change 5g into centigrams
1g = 100cg
Therefore, 5 x 100cg = 500cg
Conversion of measures from lower to higher units
We always divide when we change lower unit to higher unit.
Example 1: Change 4000g to kilogram
1000g = 1kg
Therefore, 4000 ÷ 1000 = 4kg
Addition and Subtraction
Step1: Write the units on the top.
Step2: Write the numbers in proper place below the units. Write zero in empty place.
Example 1: Add 41kg 36g and 24kg 3g
Step2: Write the numbers in proper place below the units. Write zero in empty place.
Example 1: Add 41kg 36g and 24kg 3g
Example 2: Subtract 10kg 39g from 14kg 39g
Metric Measure of Capacity
The maximum amount that something can hold is called capacity. The standard unit of capacity is liter. We use different units to measure different capacity. Milliliter, centiliter , deciliter are smaller unit used to measure smaller capacity, liter is commonly used to measure capacity, whereas units like decaliter, hectoliter and kiloliter are used to measure larger capacity. All these units are related to each other.
When we move from one metric unit to another to the right in the above metric chart, the value of metric unit becomes ten times smaller i.e. one tenth and when we move from one metric unit to another to the left in the metric chart, the value of metric unit becomes ten times bigger.
We consider liter as the basic unit of capacity.
1 Decaliter (dal) = 10 times liter
1 Hectoliter (hl) = 100 times liter
1 Kiloliter (kl) = 1000 times liter
1 Deciliter (dl) = 1/10 of liter
1 centiliter (cl) = 1/100 of liter
1 milliliter (ml) = 1/1000 of liter
1 Hectoliter (hl) = 100 times liter
1 Kiloliter (kl) = 1000 times liter
1 Deciliter (dl) = 1/10 of liter
1 centiliter (cl) = 1/100 of liter
1 milliliter (ml) = 1/1000 of liter
Conversion of measures from higher to lower units
We always multiply when we change higher unit to lower unit.
Example 1: Change 6kl into liters
1kl =1000l
Therefore, 6 x 1000l = 6000l
Example 2: Change 45l into centiliters
1l = 100cl
Therefore, 45 x 100cl = 4500cl
Therefore, 6 x 1000l = 6000l
Example 2: Change 45l into centiliters
1l = 100cl
Therefore, 45 x 100cl = 4500cl
Conversion of measures from lower to higher units
We always divide when we change lower unit to higher unit.
Example 1: Change 8000l to kilo liter
1000l = 1kl
Therefore, 8000 ÷ 1000 = 8l
Example 1: Change 8000l to kilo liter
1000l = 1kl
Therefore, 8000 ÷ 1000 = 8l
Addition and Subtraction
Step1: Write the units on the top.
Step2: Write the numbers in proper place below the units. Write zero in empty place.
Example 1: Add 40kl 34l and 23kl 3l
Example 2: Subtract 40kl 34l from 70kl 64l
Now let's watch the videos to help you understand better.
ASSIGNMENTS
Do Chapter-12 ,Exercises B+C full in ex-bk.
06 / 10 / 2021
Ch-12 Measures of Length, Mass and Capacity
( Download Ch-12 in pdf by clicking on the chapter's name above.)
Page nos:-124-127
( Download Ch-12 in pdf by clicking on the chapter's name above.)
Page nos:-124-127
In measurement chart we will learn about different types of conversions, we are going to learn math conversion of length, mass and capacity and after going through this units, the learner will be able to learn the measurement of length, measurement of mass and measurement of capacity from one unit to another, both from a smaller unit to a larger unit and vice-versa.
Metric Measure of Length
Measurement of something from its one end to the other is called its length. The standard unit of length is meter. We use different units to measure different lengths. Millimeter, centimeter , decimeter are smaller unit used to measure smaller distance, meter is used to measure average distance, whereas units like decameter, hectometer and kilometer are used to measure longer distance. All these units are related to each other.
Changing Metric Units of Length
When we move from one metric unit to another to the right in the above metric chart, the value of metric unit becomes ten times smaller i.e. one tenth and when we move from one metric unit to another to the left in the metric chart, the value of metric unit becomes ten times bigger.
Conversion of measures from higher to lower units
We always multiply when we change higher unit to lower unit.
Example 1: Change 4km into meters
1km =1000m
Therefore, 4 x 1000m = 4000m
Conversion of measures from lower to higher units
We always divide when we change lower unit to higher unit.
Example 1: Change 6000m to kilometer
1000m = 1km
Therefore, 6000 ÷ 1000 = 6km
Addition and Subtraction
Step1: Write the units on the top.
Step2: Write the numbers in proper place below the units. Write zero in empty place.
Example 1: Add 45km 34m and 34km 5m
Example 2: Subtract 15km 30m from 35km 45m
Now let's watch the video to help you understand better.
ASSIGNMENTS
Do Exercise-12A Nos 1-8 ( a+b ) and Nos 9 to 25 full pages 128-129 in ex-bk.
04 / 10 / 2021
Chapter-11 Unitary Method
( Download Ch-11 in pdf by clicking on the chapter's name above.)
( Download Ch-11 in pdf by clicking on the chapter's name above.)
Page nos:-121-122
In unitary method we will learn how to find the value of a unit from the value of a multiple and the value of a multiple from the value of a unit.
When we go to the market to buy any article, we ask the shopkeeper to tell the price of the article. This is called unit price. We calculate the price of number of articles, we want to buy, with the help of this unit price. Sometimes, we calculate unit price when the price of a multiple is given. The method to calculate the price of the required articles is called unitary method.
Generally, first we find the value of one article from the value of a multiple and then we find the value of the desired number of articles from the value of one. Usually this method involves the operations of multiplication and division both.
For example,
(i) A pack of 6 balls costs $ 48 and we have to buy 4 balls.
(ii) 20 oranges cost $ 60 and we have to buy 8 oranges.
(iii) The cost of 100 kg of wheat is $ 850 and we have to buy 40 kg of wheat.
In all such cases, first we find the unit cost for calculating the cost of the desired number of articles. To find the unit cost we divide the cost of many articles by the number of articles.
Let us consider some examples on unitary method:
1. 2 balls cost $ 8. Find the cost of 3 balls.
Cost of 2 balls = $ 8
Cost of 1 ball = $ 8 ÷ 2 = $ 4
Cost of 3 balls = $ 4 × 3 = $ 12
2. Cost of 1 book is $ 20. What is the cost of 10 such books?
Cost of 1 book = $ 20
Cost of 10 books = $ 20 × 10
= $ 200
3. 12 oranges cost $ 72. Find the cost of 4 oranges.
Cost of 12 oranges = $ 72
Cost of 1 orange = $ 72 ÷ 12 = $ 6
Cost of 4 oranges = $ 6 × 4 = $ 24
Now let's watch the video to help you understand better.
ASSIGNMENTS
Do Exercise-11A Nos 1,3,5,7,9,11,13,15,17,19,21,23 and 25 page-123 in ex-bk.
15 / 09 / 2021
REVISION
Chapter- 7 Factors and Multiples ( Including H.C.F and L.C.M.)
Revise Chapters-7 and 8 all exercises.
13 / 09 / 2021
REVISION
Chapter- 9 Decimal Fractions
Chapter-10 Money
ASSIGNMENTS
Revise Chapters-9 and 10 all exercises.
08 / 09 / 2021
Chapter-10 Money
Page nos:-116-119
Chapter-10 Money
Page nos:-116-119
In multiplication of money we will learn how to multiply the amounts of money involving rupees and paisa. We carryout multiplication with money the same way as in decimal numbers. We put decimal point after two places from the right in the product.
Worked-out examples on multiplication of money:
1. Multiply Rs. 9.25 by 4
Solution:
(i) Amounts to be multiplied by a number
(ii) The decimal point is placed after two digits from the right in the product since we see in the multiplicand the decimal point is placed after two digits from the right.
Rs. 9.25
× 4
Rs. 37.00
× 4
Rs. 37.00
In division of money we will learn how to divide the amounts of money by a number. We carryout division with money the same way as in decimal numbers. We put decimal point in the quotient after two places from the right.
The process of division of money is performed as the ordinary division of a number.
Worked-out examples on division of money by a number:
Hence Rs. 38.58 ÷ 6 = Rs. 6.43
Now let's watch the videos to help you understand better.
ASSIGNMENTS
Do Chapter-10, Exercises E + F + G full in ex-bk.
06 / 09 / 2021
(Download Ch-10 in pdf by clicking on the chapter's name above.)
Page nos:- 112-116
In addition of money we will learn how to add the amounts of money involving rupees and paisa together. We carryout with money the same way as in decimal numbers.
Addition without conversion:
(i) Rupees and paisa are arranged in columns. The decimal points are exactly in one line.
(ii) The given amounts are added as ordinary numbers.
(iii) The decimal point is placed in the sum.
Addition in money by using without conversion method we arrange the amount in columns i.e., paise under paise, rupees under rupees and dot under dot. Now add as usual as ordinary numbers.
Mary went to the shop and bought apples for Rs. 45.50 and oranges for Rs 57.63. How much money did she spend in all?
Let us help Mary in finding the total amount she spent in the shop. To find this, we need to add Rs. 45.50 and Rs. 57.63.
To add, we will arrange the amount in columns i.e., paise under paise, rupees under rupees and dot under dot. Now, add them as usual like ordinary numbers.
Step I: Arrange Rs. and paise in columns.
Step II: Add 45.50 + 57.63
Mary spent Rs. 103.13 p
Subtraction without conversion:
Subtraction in money by using without conversion method we arrange the given amounts in columns. Such that paise comes under paise, rupees come under rupees and dot comes under dot. The given amounts are subtracted as ordinary numbers. The decimal point is placed in the difference.
Consider some of the examples:
1. Subtract Rs 32.84 from Rs 72.98
Rs 72.98
- Rs 32.84
Rs 40.14
- Rs 32.84
Rs 40.14
Now let's watch the videos to help you understand better.
ASSIGNMENTS
Do Chapter-10, Exercises A + B + C + D full in ex-bk.
01 / 09 / 2021
Ch:9 Decimal Fractions
Page nos:- 101-109
Equivalent Decimal Fractions
Equivalent decimals are two decimal numbers that are equivalent, that is, they represent the same value or amount.
Here, both the decimal numbers show the same amount of space taken.
Like and Unlike Decimals
Decimals having the same number of decimal places are called like decimals i.e. decimals having the same number of digits on the right of the decimal point are known as like decimals. Otherwise, decimals not having the same number of digits on the right of the decimal point are unlike decimals.
Examples on like and unlike decimals:
5.45, 17.04, 272.89, etc. are like decimals as all these decimal numbers are written up to 2 places of decimal.
7.5, 23.16, 31.054, etc. are unlike decimals. As in 7.5 has one decimal place. 23.16 has two decimal places. 31.054 has three decimal places
Note:
If we put any number of annexing zeroes on the right side of the extreme right digit of the decimal part of a number does not alter the value of the number. So, unlike decimals can always be converted into like decimals by annexing required number of zeros on the right side of the extreme right digit in the decimal part.
For example;
9.3, 17.45, 38.105 are unlike decimals. These decimals can be re-written as 9.300, 17.450, 38.105 so now, these are like decimals.
Suppose 0. 1 = 0. 10 = 0. 100 etc, 0.5 = 0.50 = 0.500 etc, and so on. That is by annexing zeros on the right side of the extreme right digit of the decimal part of a number does not alter the value of the number.
Three different types of questions based on comparing decimals:
A. First compare the whole number part of the decimal number. Decimal with the greater whole number is greater.
1. Compare 23.14 and 8.67
Solution:
In 23.14 the whole number part is 23 and in 8.67 the whole number part is 8.
But 23 > 8
Therefore, 23.14 > 8.67
A. First compare the whole number part of the decimal number. Decimal with the greater whole number is greater.
1. Compare 23.14 and 8.67
Solution:
In 23.14 the whole number part is 23 and in 8.67 the whole number part is 8.
But 23 > 8
Therefore, 23.14 > 8.67
B. If the whole number part is the same, then compare the digit at the tenths place. The decimal with the greater tenths digit is greater.
2. Compare 53.47 and 53.81.
Solution:
In 53.47 and 53.81, the whole number part is the same, i.e., 53.
In 53.47, the decimal part is .47 and the digit in the tenths place is 4.
In 53.81, the decimal part is .81 and the digit in the tenths place is 8.
But 8 > 4
Therefore, 53.81 > 53.47
In 53.47, the decimal part is .47 and the digit in the tenths place is 4.
In 53.81, the decimal part is .81 and the digit in the tenths place is 8.
But 8 > 4
Therefore, 53.81 > 53.47
C. If the whole number part and the digit in the tenths place are the same, then compare the digit at the hundredths place and so on.
3. Compare 81.39 and 81.37.
Solution:
In 81.39 and 81.37, the whole number part is the same, i.e., 81.
In 81.39 and 81.37, the decimal part in the tenths place is the same, i.e., 3
In 81.39, the decimal part is .39 and the digit in the hundredths place is 9.
In 81.37, the decimal part is .37 and the digit in the hundredths place is 7.
But 9 > 7
Therefore, 81.39 > 81.37
In 81.39 and 81.37, the decimal part in the tenths place is the same, i.e., 3
In 81.39, the decimal part is .39 and the digit in the hundredths place is 9.
In 81.37, the decimal part is .37 and the digit in the hundredths place is 7.
But 9 > 7
Therefore, 81.39 > 81.37
Now let's watch the videos to help you understand better.
ASSIGNMENTS
Do Chapter-9 Exercises C+D+E+F+G ( Nos 1,3,5,7,9,11,13,15,17,19,21 and 23 in ex-bk.
25 / 08 / 2021
(Download Ch:9 in pdf by clicking on the chapter's name above.)
Page nos:-95-100
Definition of decimal fractions:
The fractions whose denominator (bottom number) is 10 or higher powers of 10, i.e., 100, 1000, 10,000 etc., are called decimal fractions.
For example; 7/10, 7/100, 7/1000, etc, are all decimal fractions
Note: We can also write decimal fractions with a decimal point (without a denominator), that makes easier to solve math calculations like addition and multiplication on fractions.
For example in details we can write decimal fraction;
9/10 is a decimal fraction and it can also be written as 0.9
23/100 is a decimal fraction and it can also be written as 0.23
31/1000 is a decimal fraction and it can also be written as 0.031
PLACE VALUE CHART- DECIMAL FRACTIONS:
In writing any number, the position of each digit is very crucial.
When we move to the right in the above place value chart, the value of digit becomes ten times smaller i.e. one tenth and when we move to the left in the chart, the value of digit becomes ten times bigger.
One – tenth
We can write it as 0.1.
0.1 = 1/10 = One - tenth
One – hundredth
We can write it as 0.01
0.01 = 1/100 = One - hundredth
One part of 100 equal parts is one – hundredth and written as 1/100 or 0.01O
One– thousandth
We can write it as 0.001
0.001 = 1/1000 = One - thousandth
One part of 1000 equal parts is one – thousandth and written as 1/1000 or 0.001
So, 0.1, 0.01, 0.001 are decimal numbers.
Examples:
Now let's watch the videos to help you understand better.
ASSIGNMENTS
Do Chapter-9 Exercises A+B ( Nos 1,3,5,7,9,11,13,15,17,19,21,23,27,29,31,33,35,37,39,41,43 and 45 pages 98-99 and 101 in ex-bk.
23 / 08 / 2021
Ch- 8 Fraction
Page nos:- 85-93
Now let's watch the videos to help you understand better.
ASSIGNMENTS
Do Ch-8 Exercises J,K,L,M,N (Nos 1-10) pages 87,89,91,92 and 93 in ex-bk.
11 / 08 / 2021
Ch- 8 Fraction
Page nos:- 83-85
Addition of fractions with unlike denominators
Examples:
Examples:
Now let's watch the video to help you understand better.
ASSIGNMENTS
Do Exercise-8H Nos 1,3,5,7,9,11,13,15,17,19,21 and 23 page nos 83-84 and Exercise-8I Nos 2,4,6,8,10,12,14,16,18,20,22 and 24 page no 85 in ex-bk.
04 / 08 / 2021
Ch- 8 Fraction
Page nos:- 76-81
Now let's watch the video to help you understand better.
ASSIGNMENTS
Do Exercise- 8F Nos1-4 (a,c,e,f,h) page-78 and Exercise-8G Nos 1 to 4 in text book and Nos 6,8,10,12,14,16,18,20,22,24,26,28, 30,32,34,36,38,40,42,44,46,48,50,52 and 54 pages 82-83 in ex-bk.
02 / 08 / 2021
Ch- 8 Fraction
Page nos:- 72-75
Now let's watch the video to help you understand better.
ASSIGNMENT
Do Exercise- 8E Nos 1 to 28 in text book+ Nos 29-30 (a,c,e,h) 31,33,34,37,38,40,42,44,46 and 49 pages 75 and 76 in ex-bk.
28 / 07 / 2021
Ch- 8 Fraction
Page nos:- 69-71
1. Proper Fractions
Proper Fraction Definition: When Numerator<Denominator, i.e. when the numerator of a fraction is less than the denominator, the fraction is called a proper fraction.
2. Improper Fraction
Improper Fraction Definition: When Numerator > Denominator, i.e. when the numerator is greater than the denominator, the fraction is called an improper fraction.
Note that you can represent any natural number as an improper fraction as the denominator is always 1. Also, all improper fractions are either equal to or greater than 1.
3. Mixed Fraction
Mixed Fraction Definition: A fraction comprising a natural number and a fraction is called a mixed fraction.
You can convert a mixed fraction into an improper fraction and vice versa. A mixed fraction is always greater than 1.
4. Like Fraction
Like Fraction Definition: Fractions that have the same denominators are like fractions. For example, the fractions 2/7, 3/7, 5/7, and 6/7 all have the same denominator – 7. Hence, these are like fractions.
Like Fraction Definition: Fractions that have the same denominators are like fractions. For example, the fractions 2/7, 3/7, 5/7, and 6/7 all have the same denominator – 7. Hence, these are like fractions.
5. Unlike Fractions
Unlike Fraction Definition: Fractions that have different denominators are unlike fractions. For example, the fractions 2/3 and 1/4 have different denominators. So, they are unlike fractions.
Unit Fractions
A fraction whose numerator is one and the denominator is a positive integer is called a unit fraction. Examples of unit fractions are 1/2, 1/8, etc.
Now let's watch the videos to help you understand better.
ASSIGNMENTS
Do Exercise-8D Nos 1-5 ( a,b,c,d,e ) and Nos 6-10 pages 71 -72 in ex-bk.
26 / 07 / 2021
Ch- 8 Fraction
Page nos:- 62-68
Equivalent Fractions
FRACTIONS IN THEIR LOWEST TERMS OR IN SIMPLEST FORM
Now let's watch the videos to help you understand better.
ASSIGNMENTS
Do Exercise- 8B Nos 1-8 ( a,b,c ) pages 65-66 and do Exercise- 8C full page 68 in ex-bk.
19 / 07 / 2021
( Download Ch:8 in pdf by clicking on the chapter's name above.)
Page nos:-57-60
What is Fraction?
Fractions represent equal parts of a whole or a collection.
Fraction of a whole: When we divide a whole into equal parts, each part is a fraction of the whole.
For example,
Fraction of a whole: When we divide a whole into equal parts, each part is a fraction of the whole.
For example,
Fraction of a collection: Fractions also represent parts of a set or collection.
For example,
There are total of 5 children.
3 out of 5 are girls. So, the fraction of girls is three-fifths ( 3⁄5 ).
2 out of 5 are boys. So, the fraction of boys is two-fifths ( 2⁄5 ).
For example,
There are total of 5 children.
3 out of 5 are girls. So, the fraction of girls is three-fifths ( 3⁄5 ).
2 out of 5 are boys. So, the fraction of boys is two-fifths ( 2⁄5 ).
Fraction notation
A fraction has two parts. The number on the top of the line is called the numerator. It tells how many equal parts of the whole or collection are taken. The number below the line is called the denominator. It shows the total divisible number of equal parts the whole into or the total number of equal parts which are there in a collection.
A fraction has two parts. The number on the top of the line is called the numerator. It tells how many equal parts of the whole or collection are taken. The number below the line is called the denominator. It shows the total divisible number of equal parts the whole into or the total number of equal parts which are there in a collection.
Fractions on a number line: Fractions can be represented on a number line, as shown below.
For examples,
Real life examples
The most common examples of fractions from real life are equal slices of pizza, fruit, cake, a bar of chocolate, etc.
The most common examples of fractions from real life are equal slices of pizza, fruit, cake, a bar of chocolate, etc.
Non-examples
When the parts of the whole are unevenly divided, they don’t form fractions.
Now let's watch the video to help you understand better.
ASSIGNMENTS
Study and practice Ch: 8 pages 57 to 60 and do Exercise-8A full, page-61 in ex-bk.
14 / 07 / 2021
Ch: 7 Factors and Multiples ( Including H.C.F. and L.C.M. )
Page nos:- 54-56
LEAST COMMON MULTIPLE ( L.C.M.)
Properties of L.C.M.
LCM by Short-Cut Method
Now let's watch these videos to help you understand better.
ASSIGNMENTS
Do Exercise-7E Nos 2,4,6,8,10,12,14,16,18,20,22,24,25 and 27
page no-56 in ex-bk.
12 / 07 / 2021
Ch: 7 Factors and Multiples ( Including H.C.F. and L.C.M. )
Page nos:-53-54
The H.C.F. or G.C.F. of two or more whole numbers is the greatest whole number which is a factor of both or all the numbers.
HCF by Prime Factorization Method
This method states, "Write prime factorisation of each of the given numbers. Then find out the product of all common prime factors of the numbers, using each common prime factor the least number of times it appears in the prime factorisation of any of the numbers."
Example: Find the HCF of 15 and 35.
Prime factors of 15 = 3, 5
Prime factors of 35 = 5, 7
Common factor of 15 and 35 = 5
Therefore, Highest common factor (H.C.F) of 15 and 35 = 5
Now let's watch these videos to help you understand better.
ASSIGNMENTS
Do Exercise-7D Nos 1,3,5,7,9,11,13,15,17,19,21,23 and 25 page no 54 in ex-bk.
07 / 07 / 2021
Ch: 7 Factors and Multiples ( Including H.C.F. and L.C.M. )
Page nos:-51 and 52.
Tests For Divisibility Of Numbers
In order to find whether or not a number is divisible by the another number, we perform actual division and see if the remainder is zero or not. In case the remainder is zero,we say that the given number is divisible by another number. But the process of actual division is both time consuming and complicated. In order to save a lot of time and calculations, there are some divisibility tests. Here we give the divisibility tests of numbers by 2,3,4,5,6,8,9,10 and 11.
Now let's watch the video to help you understand better.
ASSIGNMENTSStudy and practice Tests For Divisibility Of Numbers page nos- 51 and 52 and do Exercise-7C Nos 1-4 ( a, b and c) in ex-bk page no- 53.
05 / 07 / 2021
Ch:7 Factors and Multiples ( Including H.C.F. and L.C.M. )
Page nos:- 48-50
Even and Odd numbers
Prime and Composite numbers
Prime Factorisation
Prime factor : A factor of a number which is also a prime number is called the prime factor of that number.
Prime Factorisation :A factorization in which every factor is prime, called prime factorisation of the number.
Now let's watch the videos to help you understand better.
ASSIGNMENTS
Learn the definitions of even, odd, prime and composite numbers + do Exercise-7B full in ex-bk page nos- 50-51.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
16 / 06 / 2021
Ch:7 Factors and Multiples ( Including H.C.F. and L.C.M. )
(Download Ch-7 in pdf by clicking on the chapter's name above.)
(Download Ch-7 in pdf by clicking on the chapter's name above.)
Page nos:-46-47
Multiples
Now let's watch the videos to help you understand better.
ASSIGNMENTS
Do Exercise-7A full in ex-bk, page no 48.
14 / 06 / 2021
(Download Ch-6 in pdf by clicking on the chapter's name above)
Page nos:- 44-45
Now let's watch the videos to help you understand better.
ASSIGNMENTS
Do Exercise- 6A full in ex- bk,page no 45.
09 / 06 / 2021
Page nos:- 41 - 43
WORD PROBLEMS
Example- If 9975 kg of wheat is packed in 95 bags, how much wheat will each bag contain?
Solution:
Since 95 bags contain wheat 9975 kg
Since 95 bags contain wheat 9975 kg
Therefore, 1 bag contains wheat (9975 ÷ 95) kg
= 105 kg
Each bag contains wheat = 105 kg
Now let's watch the videos to help you understand better.
REVISION
Chapter:- 1 Large Numbers (Upto Ten Lakhs)
Chapter:- 2 Addition
ASSIGNMENTS
Do Exercise- 5C Nos 1,3,5,7,9,11,13,15,17,19 and 21 page nos 42 and 43 in ex-bk and revise chapters 1 and 2.
07 / 06 / 2021
(Download Ch-5 in pdf by clicking on the chapter's name above)
Page nos:- 35 - 40
DIVISION BY 10, 100 AND 1000
When a number is divided by 10, the digits, except the digit at the one's place, make the quotient and the digit at one's place becomes the remainder.
As for example:
Divide 868 by 10.
Solution:
Thus, when a number is divided by 10, the remainder is always the digit of the unit place and the quotient is the number made by the remaining digits.
When a number is divided by 100, the quotient is the number made by the digits, except the digits at one's and ten's places. The number formed by ten's and one's digit of the dividend number is the remainder.
As for example:
Divide 396 by 100.
Thus, when the dividend number is divided by 100, the extreme right two digits form the remainder and the rest of the digits form the quotient.
When a number is divided by 1000, the quotient is the number made of the digits except the digits at one's, ten's and hundred's place. The number formed by these three digits is the remainder.
As for example:
Divide 4129 by 1000.
Solution:
Thus, when the dividend number is divided by 1000, the extreme right three digits form the remainder and the rest digit/digits form the quotient.
Now let's watch the videos to help you understand better.
ASSIGNMENTS
Do Exercise-5A Nos 1,3,5,7,9,11,13,15,17,19,21,23,25,27,29 and 31 page no 39 and Exercise-5B Nos 2,4,6,8,10,12,14,16,18 and 20 page no 41 in ex-bk.
02 / 06 / 2021
Chapter- 4 Multiplication
Page no:- 31
Page no:- 31
WORD PROBLEMS
Page no:-33
Now let's watch the videos to help you understand better.
ASSIGNMENTS
Do Exercise-4B
Nos 2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34,36,38,40,42,44,46,48 and 50 page no 32 and Exercise-4C Nos 1,3,5,7,9,11,13,15,17,19 and 21 page no 34 in ex-bk.
31 / 05 / 2021
Chapter-3 Subtraction
Page no:-25
Chapter- 4 Multiplication
(Download Ch- 4 in pdf by clicking on the chapter's name above.)
Page nos:- 28-30
In this class we shall study the multiplication of 4-digit or more digit numbers by a number of two or three digits.
We know the following multiplication facts:
1. Multiplication is a repeated addition. Example : 15 + 15 + 15 = 45 or 15 x 3 = 45.
2. The number to be multiplied is called Multiplicand.
3. The number by which we multiply is called Multiplier.
4. The answer (or the result of multiplication) is called Product.
Now let's watch the videos to help you understand better.
ASSIGNMENTS
Do Exercise-3C Nos 1,3,5,7,9,11,13,15,17,19,21,23,25 and 27 page nos 26-27 and Exercise-4A full page no 30 in ex-bk.
24 / 05 / 2021
Chapter- 3 Subtraction
(Download Ch- 3 in pdf by clicking on the chapter's name above)
Page nos:- 19-24
Chapter- 3 Subtraction
(Download Ch- 3 in pdf by clicking on the chapter's name above)
Page nos:- 19-24
Now let's watch the videos to help you understand better.
ASSIGNMENTS
Do Exercise-3A Nos 1-24 in text book and Nos 25,27,29,30,32,34,36 and 39, page nos 22-23 in ex-bk and Do Exercise-3B Nos 1,3,5,7,9,11,13 and 15 page no-24 in ex-bk.
19 / 05 / 2021
Chapter- 2 Addition
Page nos:- 16-17
Page nos:- 16-17
Now let's watch the video to help you understand better.
ASSIGNMENTS
Do Exercise- 2B full in your ex-bk page no-18.
17 / 05 / 2021
(Download Ch- 2 in pdf by clicking on the chapter's name above.)
Page nos:- 12-14
Page nos:- 12-14
Now let's watch the video to help you understand better.
ASSIGNMENTS
Do Exercise- 2A Nos 1-24 in your text book and Nos 25-33 in your ex-bk page nos- 15-16.
Do Exercise- 2A Nos 1-24 in your text book and Nos 25-33 in your ex-bk page nos- 15-16.
12 / 05 / 2021
Ch-1 Large Numbers ( Upto Ten Lakhs )
Page nos:-7-9
Definition of Successor:
The number which comes immediately after a particular number is called its successor.
How to find the successor of a number?
The successor of a whole number is the number obtained by adding 1 to it.
Clearly, the successor of 0 is 1; successor of 1 is 2; successor of 2 is 3 and so on.
We observe that every whole number has its successor.
Definition of Predecessor:
The number which comes just before a particular number is called its predecessor.
The predecessor of a whole number is one less than the given number.
How to find the predecessor of a number?
Clearly, the predecessor of 1 is 0; predecessor of 2 is 1; predecessor of 3 is 2 and so on.
The whole number 0 does not have any predecessor.
We observe that every whole number, other than zero, has its predecessor.
SKIP-COUNTING
If starting with the given number, we write some numbers with a fixed gap between two successive numbers, then such a counting is called as skip counting
Rules for Comparison of Numbers:
Rule I: We know that a number with more digits is always greater than the number with less number of digits.
Example:
Which is greater?
(i) 20,36,15,589 or 6,59,76,456
Solution:-20,36,15,589 or 6,59,76,456
The number 20,36,15,589 has 9-digits and 6,59,76,456 has 8-digits.
Rule II: When the two numbers have the same number of digits, we start comparing the digits from left most place until we come across unequal digits.
Example:
Compare 29,384 and 20,364
Both numbers are 5-digit numbers.
Let us compare the digits in left most place, we find that both numbers have same digit. Next, we compare the digits in the second most left place, we find that 9> 0.
So, 29,384 > 20,364
Ascending Order:
When the numbers are arranged from the smallest to the largest number, those numbers are said to be in an ascending order.
Descending Order:
When the numbers are arranged from the largest to the smallest number, those numbers are said to be in descending order.
Now let's watch the videos to help you understand better.
Video-1 Successor and Predecessor
Video-1 Successor and Predecessor
ASSIGNMENTS
Do Exercise-1B Nos 6-16 page nos-10 and 11 in ex-bk.
10 / 05 / 2021
Ch-1 Large Numbers ( Upto Ten Lakhs )
Page nos:-4-6
Indian Place-Value Chart
We know that in the Indian place-value chart, we move from right to left. Each place-value represents 10 times the place-value to its immediate right. The following place-value chart shows nine places. Starting from the right the nine places are grouped into four periods namely ones, thousands, lakhs and crores. Each period is separated by a comma.
To read a large number we say, the name for the number followed by the name of the period from left to right. To write a large number from word form to the standard form we substitute digits corresponding to the number for each period from left to right. We use commas in place of periods names.
When a period contains zero, we do not name that period in the word form.
Solved Examples on Indian Place-Value Chart:
1. Insert commas and express the following numbers in figures.
Seventy-four crore, three lakhs, forty-one thousand six hundred four.
Solution:
Starting from left we enter the digits from crores, lakhs, thousands and ones in the following place-value chart.
Thus, the above number is read as 74,03,41,604.
2. Write the number 6,51,90,949,in words.
Solution:
We enter the digits in the places-value chart starting from right to left.
The number is written as six crore, fifty-one lakh, ninety thousand, nine hundred forty-nine.
The place value chart of the International System is given below:
100,000 = 100 thousand
1,000,000 = 1 million
10,000,000 = 10 millions
100,000,000 = 100 millions
EXPANDED FORM
We know that the number written as sum of the place-values of its digits is called the expanded form of a number.
In expanded form of a number, the number is shown according to the place values of its digits.
In 2385, the place values of the digits are given below:
Hence, 2385 = 2000 + 300 + 80 + 5
Thus, 2000 + 300 + 80 + 5 is the expanded form of 2385.
Now let's watch the videos to help you understand better.
Video-1 Indian and International Place Value System
Video-2 Expanded Form
Video-1 Indian and International Place Value System
Video-2 Expanded Form
ASSIGNMENTS
Do Exercise-1B Nos 1-5 page no-10 in ex-bk.
05 / 05 / 2021
Ch- 1 Large Numbers ( Upto Ten Lakhs )
Page nos :- 2 and 3
Page nos :- 2 and 3
Numbers showing on an abacus helps the students to understand the number and its place value. Abacus is very helpful to understand the concept of magnitude and name of a number. We know that the spike-abacus represents the number of multi-digits where the digits are represented by the spikes of the abacus.
The spikes from right to left represent the places of the place values of the digits in increasing order i.e., 1, 10, 100, ………. etc.
These places are denoted by O (unit or ones), T (tens), H (hundreds), Th (thousands), T th (ten thousands), H th (hundred thousands) and so on ……… .
From the above abacus we can count the beads from right to left and then write the exact number i.e., 51643.
O (unit or ones) ----- In ones or unit place we see 3 beads.
T (tens) ----- In tens place we see 4 beads.
H (hundreds) ----- In hundreds place we see 6 beads.
Th (thousands) ----- In thousands place we see 1 bead.
T th (ten thousands) ----- In ten thousands place we see 5 beads. Thus 51,634 is read as fifty one thousand six hundred forty three.
Now let's watch the video to help you understand better.
ASSIGNMENTS
Do Exercise-1A Nos 1-9 page nos 3-4 in ex-bk.
03 / 05 / 2021
Ch- 1 Large Numbers ( Upto Ten Lakhs )
(Download Ch- 1 in pdf by clicking on the chapter's name above.)
Page nos :- 1 and 2
(Download Ch- 1 in pdf by clicking on the chapter's name above.)
Page nos :- 1 and 2
INTRODUCTION
‘Numbers rule the Universe’. They play an important role in Mathematics. Numbers can be expressed in figures as well as words.
Numeral of a Number : The group of figures representing a number is called the numeral of that number.
Numbers Beyond 9999
We know that, the
Greatest 3digit number → 999 + 1 = 1000 ← Smallest 4- Digit Number.
Greatest 4digit number → 9999 + 1 = 10000 ← Smallest 5- Digit Number.
We read 10000 as "Ten Thousand".
In the place value chart the fifth place from the right is called the "Ten Thousands Place".
TTH | TH | H | T | O |
1 | 0 | 0 | 0 | 0 |
Each number beyond 10000 can be obtained by adding 1 to the number.
Let's have a look at some of the 5 -digit numbers.
NUMERAL | HOW WE READ |
10000+1=10001 | TEN THOUSAND ONE |
10001+1=10002 | TEN THOUSAND TWO |
10002+1=10003 | TEN THOUSAND THREE |
10999+1=11000 | ELEVEN THOUSAND |
20000+1=20001 | TWENTY THOUSAND ONE |
20001+1=20002 | TWENTY THOUSAND TWO |
99998+1=99999 | NINETY NINE THOUSAND NINE |
99999 is the largest 5 Digit Number.
Now, 99999 + 1 = 100000 is the smallest 6- Digit Number.
We read 100000 as "One lakh".
In the place value chart, the sixth place from the right is called the lakh's place.
L | TTH | TH | H | T | O |
1 | 0 | 0 | 0 | 0 | 0 |
In the place value chart, the sixth place from the right is called the lakh's place.
We add 1 to 100000 to get 100001. Further, we add 1 to 100001 to get the next number i.e., 100002. Continuing in this manner, we get 999999 as the largest 6 digit number.
We read 999999 as nine lakh ninety nine thousand nine hundred and ninety nine.
Again 999999 + 1 = 1000000 ,this is the smallest 7- digit number.
We read 1000000 as Ten Lakh.
In the place value chart, the seventh place from the right is called the ten lakh's place.
TL | L | TTH | TH | H | T | O |
1 | 0 | 0 | 0 | 0 | 0 | 0 |
Let's have a look at the following place value chart.
TL | L | TTH | TH | H | T | O |
TEN LAKHS | LAKHS | TEN THOUSAND | THOUSAND | HUNDRED | TENS | ONES |
The value of a place to the left of any digit in a number is 10 times, two places to the left is 100 times, three places to the left is 1000 times and so on.
Now let's watch the video to help you understand better.
Video-1 Large Numbers
Video-1 Large Numbers
ASSIGNMENTS
Study and practice Ch-1 page nos 1-2.
Study and practice Ch-1 page nos 1-2.
