QR Code Chapter 10

10. Tenths and Hundredths

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

How long is this pencil ? Guess _____ cm

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

We can see that Anju used a lens to make it look bigger.

It is more than 3 centimetres.

A pencil is kept over a ruler and a magnifying glass is used to check the length of the pencil.

Here one centimetre has 10 equal parts. So each part is one-tenth of a centimetre.

One-tenth of a centimetre is called one millimetre (mm).

Oh, so this pencil is 3 centimetres and 6 millimetres long.

See I am 3 mm long!

But I am longer! Seven-tenth of a centimetre or _____ millimetres

A magnifying glass used to check the length of an ant on a ruler.

A magnifying glass used to check the length of a butterfly on a ruler.

We also call one-tenth of a centimetre as 0.1 centimetre. We read it as ‘zero point one centimetre’.

So one millimetre is the same as 0.1 cm.

1. What is the length of this pencil? _____ mm.

What is its length in centimetres?

A magnifying glass used to check the length of a small pencil on a ruler.


Have you seen frogs? Where? How many different types of frogs have you seen? Are all the frogs of the same length? Here are two interesting examples.

Gold Frogs

This kind of frog is among the smallest in the world. Its length is only 0.9 cm!

Guess how many such frogs can sit on your little finger!

Bull Frog

But this is among the biggest frogs.

It is as long as 30.5 cm!

A small frog is sitting on a boy's finger and a big frog is sitting on his hand.

What does 0.9 cm mean? It is the same as _____ millimetres. We can also say this is nine-tenths of a cm. Right?

So 30.5 cm is the same as _____ cm and _____ millimetre.

About how many of the big frogs will fit on the 1m scale? _____

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

Practice time

1) Length of the - nail cm and _____ mm or 2. _____ m.

A magnifying glass used to check the length of a nail on a ruler.


A ladyfinger is kept on a ruler.

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

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

Three candles marked candle 1, candle 2 and candle 3 respectively. Candle 1 is the smallest ad candles 3 is the tallest.

Length of

Length in cm and mm

Length in cm

Candle 1

Flame 2

Candle 2

Flame 2

Candle 3

Flame 3

Guess and Colour

First colour the rods as shown, without measuring! Then check.

Rods of length less than 1 cm Red

Rods of length between1 cm and 2 cm Blue

Rods of length between 2 cm and 3 cm Green

Rods of length between 3 cm and 4 cm Orange

Cylindrical rods of different sizes.

Guess, Draw and Measure

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?

Guess its length and draw

Measure of your drawing

Measure of your friend's drawing

An ant of length less than 1 cm

Pencil of length about 7 cm

A glass 11 cm high with water up to 5 cm

A bangle of perimeter 20 cm

A curly hair of length 16 cm

Our Eyes Get Confused?

Which line is longer? A or B? Measure each line and write how long it is in centimetres. How good is your guess?

Two lines are drawn, A is written over the first line and B is written over the second and a girl is looking at them.

A boy is looking at a line C drawn perpendicular to another line D.

Which line is longer? C or D? Measure each line.How good is your guess?

Whose Tail is the Longest?

Guess whose tail is the longest. Now measure the tails. How good is your guess?

A cat

A dog

A monkey sitting on a pig.

The Longest Rupee Notes?

What is the length of a 100 rupee note? Guess.

Now measure it using a scale.

Now guess the length and width of many other things. Measure and find the difference between your measure and your guess.

A one hundred rupee note. It is rectangular in shape.

Size of

Your guess in cm

Your measure in cm





100 Rupee note

Post card

Math-Magic book

10 Rupee note

20 Rupee note

5 Rupee note

Post card

Math-Magic book

At the market

On a tray of eggs, it is written, rupees two point five foe one egg.

The price label of rupees one hundred twenty point five is attached to a bag.

The price label of rupees six point five is attached to a pen.

The price label of rupees five hundred sixty seven point two five is attached to a clock.

The price label of rupees eight point seven five is attached to a soap.

The price label of rupees point five is attached to a matchbox.

The price label of rupees thirty two point nine nine is attached to a pair of slippers.

Look at this funny price! 32 rupees and 99 paise! But if we give 33 rupees they don’t give us back one paisa!

What part of a rupee is 1 paisa?

A girl

This is only to fool us by showing 1 paisa less!

One paisa is one hundredth of a rupee, isn’t it?

It is written as Rupee 0.01. So that is why we write 99 paise as Rupee 0.99

A woman

1) How many paise does a matchbox cost? _____

2) How many matchboxes can be got for Rs 2.50? _____

3) How many rupees does the soap cost? _____

4) 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.

5a) An egg costs two and a half rupees. How much will one and a half dozen cost?

b) How many pens can Kannan buy? How much money is left?

Kannan, take rupees 60 and buy one and half dozen eggs. You can buy pens with the money left.


A woman giving some money to a boy.

Can I buy two pens with rupees 13?

A girl is showing her two fingers.

6) The price of two pens is Rs _____ Can she buy two pens?

Practice time — Match these

Match each yellow box with one green and one pink box

Rupee 1/2

5 paise

Rupee 0.75

Rupee 1/10

25 paise

Rupee 0.50

Rupee 5/100

99 paise

Rupee 0.05

Rupee 3/4

50 paise

Rupee 0.10

Rupee 99/100

75 paise

Rupee 0.25

Rupee 1/4

10 paise

Rupee 0.99

Colourful Design

What part of this sheet is coloured blue? _____ /10

What part of the sheet is green? _____

Which colour covers 0.2 of the sheet?

Oh, the blue strip is 0.1 of the sheet.

Some tall and some short rectangular strips drawn on a grid.

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

All the strips on the grid are divided into small square boxes.

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?

Think: Can we write ten paise as 0.1 of a rupee?

How many boxes are red? What part of the sheet is this? 15/____

Can we also write it as 0.15 of the sheet?

(Hint: remember we wrote 99 paise as 0.99 rupee!)

Now 3/100 of the sheet is black. We can say 0. _____ sheet is black.

How many white boxes are there in the sheet?

What part of the second sheet is white? _____

* Make your designs.

A blank grid.

Make a nice design by colouring 0.45 part of this square red.

A blank grid.

Use four colours. Each colour should cover 0.05 of this square.

Sports Day

The school at Malappuram has its sports day.

The first five children in the Long Jump are:

A board on which it is written, Tina three point five zero meter, Meena four point  zero five meter, Rehana four point zero five meter, Anu three point five meter and Amina thee point three five meter.

A girl is jumping very high on a track.

Teena jumped 3.50m which is 3 m and 50 cm.

But how did Anu jump? _____ m and _____ cm

Who is the winner in the long jump? _____

Write the names of the I, II and III winners on this stand.

Do you remember that 1 metre = 100 centimetres?

So one centimetre is 1/100 of a metre.

We also write 1 cm as _____ m

There are three levels in the same row, attached to each other. In the middle is the highest level, on which number one is written. Towards its each sides are levels two and three respectively, which are lower in height than level one.

Write in Metres

3 metre 45 centimetre _____ metres

99 centimetre _____ metres

1 metre and 5 centimetre _____ metres

How Big Can You Get


A girl and a boy are measuring the chest size of a fat man using measuring tape.

After breathing out 1.52 m

A girl and a boy are measuring the chest size of a fat man using measuring tape.

On taking a deep breath 1.82 m

Difference in size _____

Do this for yourself and find the difference.

B) You have to grow 45 cm more to reach 2 m height

A boy is standing against a wall and a girl is checking his height.

Practice time

1) Money from different countries

Have you seen any notes or coins used in any other country?

Shivam Bank has a chart to show us how many Indian rupees we can get when we change the money of different countries.



Changed into Indian Rupees




Sri Lanka

Rupee (SL)





Hong Kong

Dollar (HK)


South Africa


















(This is the rate on 15-2-2008)

Currencies of different countries.

A) The money of which country will cost the most in Indian Rupees?

B) Mithun’s uncle in America had sent him 10 USA dollars as a gift.

Mithun used 350 rupees for a school trip. How much money was left with him?

A bus is moving on a road between the hills and the trees.

Children are not expected to carry out long multiplication involving decimals. Instead, encourage them to think in terms of currency. For example, 75 paise × 2 can be thought of as two 50 paisa coins and two 25 paisa coins.

C) Majeed’s father is working in U.A.E. He gets 1000 Dirham as salary. Arun’s father who is working in Sri Lanka gets 2000 Sri Lankan Rupees. Who gets more Indian rupees as salary?

D) Leena’s aunty brought a present for her from China.

It cost 30 Yuan. Find what it costs in Indian rupees.

E) Astha wants some Hong Kong Dollars and Won.

1) How many Won can she change for Rs 4 For Rs 400?

2) How many Hong Kong Dollars can she change for Rs 508?

2) Kiran went shopping with Rs 200. Look at the bill. The shopkeeper forgot to put the point correctly in the prices. Put the point in the correct place and find out the total amount of the bill.

A bag, a bottle of coconut oil, a pack of tea, a soap cake.



Price (Rupees)




Green gram

1 kg



250 gm


Coconut Oil

1 Litre



3) Which city is cool?

I live in Himachal.

There the temperature in winter is 2º Celsius.

Sometimes water in pipes freezes into ice.

A man wearing a cap is checking a water pipe using a tool in his hand and a bucket is kept in front of him.

But in Rajasthan where I live the temperature reaches 48º Celsius.

Here it is very hot. One has to walk kilometres to get water.

A woman is carrying an empty pot in her hand and two pots on her head.

Children can be encouraged to look at temperatures (in degree Celsius or °C) of different cities in the news paper and on TV. Without using the terms' maximum' and 'minimum' this exercise will give them an idea that temperatures can be measured at two different times of the day. Only simple subtractions using decimals have been used here. They will also get familiar with the names of different capital cities and can do similar exercises for the capital cities of other countries.

The temperature in each city was noted at 3 pm on 16 January 2008.

1) Which place had the highest temperature at 3 pm? Which place is the coolest at that time?

In a map following places are marked with temperatures 1. Srinagar- eight point one degrees Celsius. 2. Bhopal- twenty five point nine degrees Celsius. 3. Jaipur- Twenty five point two degrees Celsius 4. Kolkata- twenty six point six degrees Celsius 5. Chennai- Twenty nine point nine degrees Celsius 6. Guwahati- Twenty four point five degrees Celsius .7. Mumbai- Five point one degrees Celsius 8. Thiruvananthapuram- Five degrees Celsius

3) How many degrees will the temperature need to rise for it to reach 40ºC in Thiruvananthapuram?

4) How much lower is the temperature of Kolkata from that in Chennai?

5) The temperature in these cities was also noted at 3 am on the same day.

Look at the table and answer the questions.

a) Which place had the lowest temperature at 3 am? Imagine yourself to be there and describe how it would feel.

b) What is the difference between the temperatures at 3pm and 3am in Chennai? In Bhopal?


Temperature at 3 am