NCERT Solutions for Class 4 Maths Chapter 7

1. The elephant is drinking 50 litres of kheer. The giraffe is drinking ___________ litres. The cow is drinking ___________ litres. 

Then came the squirrel. She said I can’t drink 1 litre of kheer, please give me only 500 millilitres. The donkey asked 500 millilitres of kheer? Isn’t that more than a litre.? The fox said Come on, don’t behave like a donkey! One litre is 1000 millilitres, so 500 millilitres is half a litre.

Ans: The giraffe is drinking 10 litres and the cow is drinking 20 litres.

2. OK., here is your kheer — said the cat, while serving the kheer. She took 10 glasses and poured 100 millilitres of kheer in each glass.

The donkey looked confused and asked — Ten glasses of 100 mL each. How much is that? The fox got another chance to show off! He said Ah, that is simple! 10 times hundred millilitres are ______________ millilitres = _____________ _ litre. Now you write it 10 × 100 mL = __________

Ans: 1 glass has 100 mL of kheer 

10 glasses have \[10{\text{ }} \times {\text{ }}100{\text{ }}mL = {\text{ }}1000{\text{ }}mL\]

So, 10 times 100 millilitres are 1000 millilitres. 

\[1{\text{ }}L{\text{ }} = {\text{ }}1000{\text{ }}mL\]

∴ 10 times 100 mL = 1000 mL 

\[1{\text{ }}L{\text{ }}10 \times 100{\text{ }}mL = {\text{ }}1{\text{ }}L\]

3. Each ant drinks 1 millilitre of kheer. So, 1000 ant’s drink: \[1000{\text{ }} \times {\text{ }}1{\text{ }}mL\]= ________ ml.

Ans: If each ant drinks 1 milliliter of kheer.

Then, 1000 ant drinks \[1000{\text{ }} \times {\text{ }}1{\text{ }}mL\]of kheer that is1000 ml that is $1000 \times 1 = 1000$ml

4. The donkey is trying to look for different ways to add up to 1 litre. Help him complete the chart.

Ans: We know \[1000{\text{ }}mL{\text{ }} = {\text{ }}1L\]

Thus, we have to make the sum of the numbers 1000 as the result is given 1 L.

Thus, the resultant box will be, 

Any student can make changes but we have to make sure that the resultant sum of the given numbers must be 1000. 

5. Look Around Look at these pictures. Now look for some other things we get in packets or bottles like these. Make your own list.

Ans: As there neither any product nor the amount of any product is mentioned here. Thus, it can be any product with any amount.

6. Collect a 1-litre bottle and some other small bottles. Guess how many times you have to pour from each of the small bottles to fill the litre bottle. Check if your guess is correct and fill the table.

Ans: As the understanding capacity of each person is different from one another. Thus, the measurements may and may not be the same.

7. Look what Adithyan is saying. How much water does his small bottle hold? __________ I poured two small bottles of water to fill this 1-litre bottle.

Adithyan: I poured two small bottles of water to fill this 1 litre bottles.

Then how much water does Leela’s bottle hold? _________ To fill the 1-litre bottle I need to pour water 5 times from my small bottle.

Ans: Ramu pours 2 small bottles of water to fill a bottle of 1 litre.

\[\;1{\text{ }}L{\text{ }} = {\text{ }}1000{\text{ }}mL\]

So, the capacity of one big bottle = 1000 mL 

To fill the big bottle if Ramu uses the small bottle 2 times then the capacity of the small bottle,\[\dfrac{{1000}}{2}{\text{ }}mL\; = 500mL\]

Therefore, Ramu can hold 500 mL of water in his bottle.

Leela pours 5 small bottles of water to fill a1 litre bottle.

\[1000{\text{ }}mL{\text{ }} = {\text{ }}1{\text{ }}L\]

So, the capacity of the big bottle = 1000 mL 

To fill the big bottle Leela uses the small bottle 5 times. 

So, the capacity of the small bottle = \[\dfrac{{1000}}{5}{\text{ }}mL = 200ml\]

Thus, Leela can hold 200 mL of water in her small bottle.

8. Ramu’s Measuring Bottle got an empty 250 mL coconut oil bottle. Look at the picture and discuss what he did to make his big measuring bottle.

Ans: Two empty bottles will be taken by Ramu, one large sized bottle and the other 250 mL coconut oil bottle. Ramu will fill a 250 mL bottle with water and then dump it all into the larger bottle.

He will now write 250 mL on the huge bottle's level.

He will repeat the operation, this time marking the level at 500 mL.

He will fill the 250 mL container again, but this time he'll record the level as 750 mL.

He will go through the process once more, this time marking the level at 1 litre.

In this way Ramu was able to make changes.

9. Neetu in Hospital Neetu has to take 3 injections in a day for 5 days. How much medicine will she need for one day?

Ans: 1 injection contains 5 mL of medication. 

Neetu will be required to receive three shots per day for the next five days.

As a result, the total amount of medicine in three injections is \[3 \times 5{\text{ }}mL = 15{\text{ }}mL.\]

As a result, Neetu will require 15 mL of medicine in one day.

15 mL is the amount of medicine Neetu requires in one day.

Neetu's pharmaceutical requirements in 5 days \[{\text{ }}5 \times 15{\text{ }}mL = 75{\text{ }}mL\]

As a result, Neetu will require 75 mL of medicine in 5 days.

10. How much do we use at a time? 

⦁ Eye dropsWe use less than 1 mL at a time. 

⦁ __________       ________________________________ 

⦁ __________      ________________________________ 

⦁ __________      _______________________________

Ans:  As in the question there is neither any particular thing mentioned nor the amount. The amounts can be varied accordingly, the given amount is not fixed for each and every person.

11. List things we use more than one litre at a time.

⦁ Water for taking bath

⦁ ______________________________________________

⦁ ______________________________________________ 

⦁ ______________________________________________

Ans: The list which we have used or consumed more than 1 L are,

⦁ Water for taking bath.

⦁ Water for washing cloth.

⦁ Water we should drink per day.

⦁ Amount of oil needed to fill a motorbike.

12. Practice Time Amina’s water bottle holds one litre of water. She drank 250 mL of water and her friend Govind drank 150 ml. How much water is left in her bottle?

Ans: Capacity of Amina’s water bottle = 1 L

\[1{\text{ }}L{\text{ }} = {\text{ }}1000{\text{ }}mL\]

Amina's water bottle has a capacity of 1000 ml.

Amina drank 250 millilitres of water.

Govind drank 150 millilitres of water.

\[250{\text{ }} + {\text{ }}150{\text{ }}mL{\text{ }} = {\text{ }}400{\text{ }}mL\]of water consumed by both

\[1000{\text{ }}mL{\text{  -  }}400{\text{ }}mL{\text{ }} = {\text{ }}600{\text{ }}mL\]of water remaining in the bottle

As a result, Amina's bottle has 600 mL of water remaining in it.

13. Practice Time Yusuf runs a tea shop. For making a glass of tea he uses 20 mL of milk. Yesterday he made 100 glasses of tea. How much milk did he use?

Ans: Yusuf used 20 millilitres of milk to create a glass of tea.

Yusuf used 100 mL of milk to make 100 glasses of tea = \[100{\text{ }}mL \times 20{\text{ }}mL = 2000{\text{ }}mL\]

To brew 100 glasses of tea, Yusuf used 2000 mL of milk.

14. Practice Time Radha’s grandma was ill. The doctor gave her a bottle with 200 mL of medicine. She has to take the medicine every morning for 10 days. How many millilitres of medicine does she have to take every morning? ________

Ans: The amount of medicine in the bottle is 200 millilitres.

Radha's grandmother was told by the doctor to take the medicine every morning for ten days.

Grandma has to take a certain amount of medicine every morning, \[\dfrac{{200}}{{10}} = 20{\text{ }}mL\]

15. Water-Water The table shows the water used in one day by a family of 5 people. They live in Gudalur village.

Total water used by them____________

Ans: 30 liters of water used for cooking and drinking.

40 liters of water were used to wash the clothing.

20 liters of water were used to clean pots and pans.

Bathing water use = 75 liters.

\[30{\text{ }} + {\text{ }}40{\text{ }} + {\text{ }}20{\text{ }} + {\text{ }}75{\text{ }} = {\text{ }}165\]L total water consumed.

16. Water-Water How many litres of water does your family use in a day? Guess and fill in this table.

Ans: Consider: \[1{\text{ }}bucket{\text{ }} = {\text{ }}5{\text{ }}L\]

17. Chelannur village has a milk society. Geetha and Ammini went there to buy 4 litres of milk. But the man could not find the one litre measure. He had only a 3 litre and a 5-litre bottle with him. But he gave them exactly 4 litres of milk. Explain how he did this.

Ans: Again, he will fill the 5-litre bottle with milk.

After pouring its content in the 3-litre bottle, 2 litres of milk are left in the 5-litre bottle. 

Now, he will now pour 2 litres of milk into the Geetha bottle once more.

Geetha's bottle now holds 4 litres of milk.

Both Geetha and Ammini get 4 litres of milk this way.

What is Capacity?

The quantity of a liquid such as water, milk or juice, etc. is called its volume. Capacity is the volume of a liquid that a container can hold. We measure volumes of liquids such as water, milk, juice, petrol, or kerosene with a container whose capacity is already known.

The standard units of capacity are liter and milliliter.

1000 millilitres (ml) = 1 litre ( l )

1000 litres (l)   = 1 kilolitre (kl)

A milliliter is a very small unit of capacity. For example, the capacity of a teaspoon is about 5 ml.

A liter is a bigger unit of capacity. For example, the capacity of a water bottle can be about 1l.

Smaller quantities of liquids are measured in milliliters and liters. Larger quantities of liquid are measured in kilolitres. The measuring cylinder is used to measure the volume of liquids.

With this concept, you will now understand what the animals are talking about at the party.

Let us now understand the conversion of capacity.

Conversion of capacity means converting a higher unit into a smaller unit or a smaller unit into a higher unit.

When we convert a larger unit, say kiloliter, into a smaller unit, say milliliter, then we multiply the quantity by 1000. When we need to convert a smaller unit, say milliliter, into a larger unit, say kiloliter, then we divide the quantity by 1000.

Example: Convert 8 liters into milliliters.

Solution: 1l = 1000 ml

8l = 8 x 1000 ml

=  8000 ml

Note: Never forget to put the units after the quantity. Marks will be deducted in your exam if you forget to put the unit.

Let us see how we use this in real-life with some examples.

Example 1: Radha drank 8 glasses of water in a day. If the capacity of a glass is 250 ml, how much water did she drink?

Solution: Capacity of 1 glass = 250 ml

Capacity of 8 glasses = 8 x 250 ml = 2000 ml = 2l

Now, we can understand the lesson properly and solve the questions given in the chapter. We need measuring containers to measure the volume of a liquid. There are various measuring containers used for measuring the quantities of liquids. You must have seen your mother using measuring containers while cooking. You also can try different experiments at home to make measuring bottles, and then you can check the quantity of water or any other liquid.

Conclusion

So what did we learn today? We learned the measurement of liquid in terms of volume. We have learned the unit of volume, and how we can convert a unit into another unit. This lesson is very helpful in our daily activities. We can check whether the milkman is giving milk in the right quantity or not. We can measure and drink water every day. We should have at least 2l of water every day to keep ourselves healthy. Whenever you offer juice or cold drinks to your friends, you can equally distribute it among them. Hence, learning the concept of volume is very beneficial for all students.