The chapter Tenths and Hundredths focuses on introducing the idea of decimals to students. It helps the students to understand the concept of the tenth or the hundredth of any given number. It covers the topics: philosophy Measuring small values in millimetres philosophy Relative measurement units philosophyDifferences in sizes philosophyEstimating values NCERT Math-Magic questions are answered in a simple and engaging manner. We have also related 'Learning Concepts and interactive worksheets with the solutions. Our 'Learning Beyond' segment caters to all the probable questions that a child might think out of curiosity. Download Chapter 10 Tenths and Hundredths in PDF format for free here.

Download the NCERT Solutions for Tenths And Hundredths in PDF

Question 1 :

a) What is the length of this pencil? __mm.

b) What is the length of this pencil in centimetres?

Answer :

a) The length of the pencil is 6 mm.

b) The length of the pencil is 0.6 cm.

Question 2 :

a) What was the length of the smallest pencil you have used?

b) How long is this pencil? Guess___ cm

c) Measure it using a scale. How good is your guess?

Answer :

a) Do it by yourself. Answers may vary.

b) Guess on your own and answer the question.

c) As shown on the ruler, the length of the pencil is 3.6 cm. Check how close your guess was.

Question 1 :

a) What does 0.9 cm mean? It is the same as __ millimetres.

b) We can also say this is nine-tenths of a cm. Right?

c) So, 30.5 cm is the same as __ cm and __ millimetre.

d) About how many of the big frogs will fit on the 1 m scale? ___

e) If they sit in a straight line about how many of the small frogs will cover 1 m? ___

Answer :

a) The relation between cm and mm is: 0.1 cm = 1 mm

b) 1 mm is one-tenth of a cm. So, we can say 9 mm is nine-tenth of a cm.

c) 30.5 cm is the same as 30 cm and 5 mm.

d) The relation between m and cm is: 1 m = 100 cm Since 1 big frog is 30.5 cm long, about 3 big frogs will fit on the 1 m scale.

e) Since 1 small frog is 0.9 cm long, about 111 small frogs will cover 1 m.

Question 1 :

Length of the nail — 2 cm and __ mm or 2. __ cm.

Answer :

The length of the nail is 2 cm and 9 mm. Since 1 mm = 0.1 cm, we can write 2 cm and 9 mm also as 2.9 cm.

Question 2 :

The length of this lady’s finger (bhindi) is __ cm and __ mm. We can also write it as __ cm.

Answer :

The length of the lady’s finger is 8 cm and 4 mm. Since 1 mm = 0.1 cm, we can also write it as 8.4 cm.

Question 3 :

Guess the lengths to draw these things. Ask your friend to draw the same. After you make the drawing use a scale to measure the length. Whose drawing showed a better guess?

Answer :

Do it by yourself. Answers may vary.

Question 4 :

How many paise does a matchbox cost?

Answer :

The cost of a matchbox is Rs 0.50.

1 rupee = 100 paise

⇒ 0.50 rupee = 50 paise.

Therefore, the cost of a match box is 50 paise.

Question 5 :

** **How many matchboxes can be got for Rs 2.50?

Answer :

Rs 0.50 is the cost of 1 matchbox.

Therefore, Rs 2.50 is the cost of 2.50 ÷ 0.50 = 5 matchboxes.

Thus, 5 matchboxes can be bought for Rs 2.50.

Question 6 :

** **How many rupees does the soap cost?

Answer :

The soap cost Rs 8.75.

Question 7 :

Arun wanted to buy a soap. He has a five-rupee coin, 2 one-rupee coins and 4 half-rupee coins. Write in rupees what money he will get back.

Answer :

Arun has:

1 five-rupee coin = Rs 5

2 one-rupee coins = Rs 2

4 half-rupee coins = Rs 2

Total amount = 5 + 2 + 2 = Rs 9

Since the cost of a soap is Rs 8.75, he will get back

9 – 8.75 = Rs 0.25.

Question 8 :

The price of two pens is Rs __.

Can she buy two pens?

Answer :

The price of one pen is Rs 6.50

⇒ The price of two pens = 2 × 6.50 = Rs 13

Therefore, she can buy two pens for Rs 13.

Question 9 :

Match each yellow box with one green and one pink box.

Answer :

Match the rupee with equivalent paise, and the rupee written in decimals. The correct answer is:

Question 10 :

a) What part of this sheet is coloured blue?__/10

b) What part of the sheet is green? __

c) Which colour covers 0.2 of the sheet?

Answer :

The sheet can be divided into 10 long strips. So, each long strip is 1/10 or 0.1 of the sheet.

a) 1 strip is coloured blue. Therefore,

part of the sheet is coloured blue.

b) Three strips are coloured green. Therefore,

or 0.3 part of the sheet is green.

c) There are 2 yellow strips. Therefore, the yellow colour covers or 0.2 of the sheet.

Question 11 :

a) Look at the second sheet. Each strip is divided into 10 equal boxes. How many boxes are there in all?

b) Is each box 1/100 part of the sheet? How many blue boxes are there? __ Is blue equal to 10/100 of the sheet? We saw that blue is also equal to 1/10 of the sheet. We wrote it as 0.1 of the sheet. Can we say 10/100 = 1/10 = 0.10 = 0.1?

c) Can we write ten paise as 0.1 of a rupee?

d) How many boxes are red? What part of the sheet is this? 15/__ Can we also write it as 0.15 of the sheet?

e) Now 3/100 of the sheet is black. We can say 0.__ sheet is black.

f) How many white boxes are there in the sheet? What part of the second sheet is white? ___

Answer :

a) Observe the given sheet. Each strip is divided into 10 equal boxes, and there are 10 strips in all.

Therefore, the total number of boxes is:

10 × 10 = 100

So, there are 100 boxes in all.

b) Since there are 100 equal boxes, each box is 1/100 of the sheet.

There are 10 blue boxes. So, the blue portion is 10/100 of the sheet.

10/ 100 = 1/10 = 0.10 = 0.1

c) There are 100 paise in one rupee. Therefore,

10 paise = 10/100 rupee = 1/10 rupee = 0.10 rupee = 0.1 rupee

d) There are 15 red boxes. Since the sheet is divided into 100 equal boxes, the red colour is 15/100 of the sheet.

15/100 = 0.15

So, the red colour is 0.15 of the sheet.

e) 3/100 of the sheet is black.

3/100 = 0.30

Therefore, 0.30 of the sheet is black.

f) There are 22 white boxes. Since there are 100 boxes in all, 22/100 part of the sheet is white.

Question 12 :

The school at Malappuram has its sports day. The first five children in the Long Jump are:

Who is the winner in the long jump? ___ Write the names of the I, II and III winners on this stand.

We can also write 1 cm as __m.

Answer :

Observe the given table and arrange the jumps in descending order. 4.50 > 4.05 > 3.50 > 3.35 > 3.05

Therefore, Rehana is the winner, and the names of the I, II and III winners are Rehana, Meena, and Teena, respectively.

Since 100 cm = 1 m,

1 cm = 0.01 m

Question 13 :

What is Dinesh’s height in metres? __ m __ cm.

Answer :

We know that 1 m = 100 cm. Therefore,

2 m = 200 cm

Since he need to grow 45 cm more to reach 2 m height, his present height is

200 – 45 = 155 cm.

Now, convert 155 cm in m and cm as:

155 cm = 1.55 m = 1 m 55 cm

Therefore, Dinesh’s height is 1.55 m or 1 m 55 cm.

Question 14 :

Using the scale on this page find the difference in length between candle 1 and candle 3.