Chapter 12: How Heavy? How Light?

Q1Written answer

Question: 1

Find out the total weight they had loaded on the cart.

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Worked solution

Answer: Weights of all the things

Things loaded	Weight	Number of items	Their total weights
A sack of wheat	100 kg	5	5 × 100 = 500 kg
A sack of rice	35 kg	3	3 × 35 = 105 kg
Water tank	50 kg	1	1 × 50 = 50 kg
Almirah	70 kg	1	1 × 70 = 70 kg
A table	10 kg	3	3 × 10 = 30 kg
A chair	5 kg	4	4 × 5 = 20 kg
A mattress	20 kg	2	2 × 20 = 40 kg
Bamboo ladder	10 kg	1	1 × 10 = 10 kg
Pots and pans	10 kg		10 kg

Total weight of all the things loaded = 500 + 105 + 50 + 70 + 30 + 20 + 40 + 10 + 10

= 835 kg

Therefore, the total weight they had loaded on the cart was 835 kg.

Q2Written answer

Question: 2

Which things should be removed so that the weight of the load is not more than 700 kg?

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Worked solution

Answer: The weight that should be removed to make the weight equal to 700 kg

= 835 – 700

= 135 kg

From the table,

The weight of 3 sacks of rice = 105 kg

The weight of 3 tables = 30 kg

Total weight of both of these two things = 105 + 30

= 135 kg

Therefore, to make the weight equal to 700 kg, they should remove 3 sacks of rice and 3 tables.

Q3Written answer

Question: 3

Now, you also make your own balance. Write down how you made it. Also, draw a picture of your balance in the box below.

NCERT Solutions Mathematics Class 4 Chapter 12 - 3

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Answer: Do it yourself.

NCERT book Page No: 135

Q4Written answer

Question: 4

NCERT Solutions Mathematics Class 4 Chapter 12 - 4

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Worked solution

Answer: We know that the geometry box is heavier than the pencil. Hence, the pan that has a geometry box will go down.

What is heavier?

Q5Written answer

Question: 5

Make pairs of different things and use the balance to decide which is heavier. First, guess which thing will take the pan down and then check your balance.

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Worked solution

Answer: Following are the pairs of different things:

(a) Pen and book

A book is heavier than a pen. So, the pan that has the book will go down.

(b) Glass and spoon

Glass is heavier than a spoon. Hence, the pan that has the glass will go down.

(c) Toothbrush and toothpaste

Toothpaste is heavier than a toothbrush. Therefore, the pan that has the toothpaste will go down.

(d) Socks and trouser

A trouser is heavier than socks. Hence, the pan that has the trouser will go down.

What is the heaviest?

Q6Written answer

Question: 6

(a) Make groups of three things. For example – eraser, ball and paper. Use the balance to arrange them in order of weight – the lightest, the one with in-between weight, and the heaviest. Complete the table with at least five examples.

NCERT Solutions Mathematics Class 4 Chapter 12 - 5

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Worked solution

NCERT Solutions Mathematics Class 4 Chapter 12 - 6

(b) Can you find your own weight using this balance?

Answer: No, we cannot find our own weight.

NCERT book Page No: 136

Making Weights

Q7Written answer

Question: 7

Get a new cake of soap. The packet will have the weight written on it. You can use this soap to make your own different weights.

The soap weighs _________ grams (g)

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Worked solution

Answer: The soap weighs 100 grams.

Q8Written answer

Question: 8

Take a small plastic packet. Put it in one pan of the balance. Put the soap in the other pan. Slowly add sand to the packet till the pans are balanced.

Close the packet with a rubber band or string. Now stick a strip of paper; how many grams will both these weigh?

NCERT Solutions Mathematics Class 4 Chapter 12 - 7

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Answer: It is written 100 gm on the packet.

Q9Written answer

Question: 9

If you put the soap and the weight you just made together in a pan, how many grams will both these weigh?

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Worked solution

Answer: Both weigh 100 + 100 = 200 gm

NCERT book Page No: 137

Practice Time

Q10Written answer

Question: 10

(a) Which pan of the balance will go down? Show by drawing an arrow.

NCERT Solutions Mathematics Class 4 Chapter 12 - 8

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Worked solution

Answer: Do it yourself.

(b) Is the weight on any of the pans equal to 1 kilogram? Mark it.

Answer: The left pan of the fourth figure weighs 1000 gm. The pan includes weights measuring 55 g, 245 g and 700 g, i.e.,

55 + 245 + 700 = 1000 g

= 1 kg

Therefore, the left pan of the fourth figure is equal to 1 kilogram.

(c) How many grams are there in 1 kg?

Answer: We know

1 kg = 1000 g

Hence, there are 1000 grams in 1 kilogram.

NCERT book Page No: 138

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