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.

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.

❈ What is the length of this pencil? _______ mm.

What is its length in centimetres?

Frogs

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 Frogs

But this is among the biggest frogs. It is as long as 30.5 cm!

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 is 2 cm and ___ mm or 2 ___ cm.

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.

$ \begin{array}{|l|l|l|} \hline \text { Length of } & \begin{array}{c} \text { Length in } \mathrm{cm} \\ \text { and } \mathrm{mm} \end{array} & \text { Length in } \mathrm{cm} \\ \hline \text { Candle 1 } & & \\ \hline \text { Flame 1 } & \\ \hline \text { Candle 2 } & \\ \hline \text { Flame 2 } & \\ \hline \text { Candle 3 } & & \\ \hline \text { Flame 3 } & & \\ \hline \end{array} $

Guess And Colour

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

$ \begin{array}{lcl} \color{red}\text{Rods of length less than 1 cm } & \quad & \color{red}\text{Red } \\ \color{blue}\text {Rods of length between1 cm and 2 cm } & \quad & \color{blue}\text {Blue }\\ \color{green}\text {Rods of length between 2 cm and 3 cm } & \quad & \color{green}\text {Green } \\ \color{orange} \text {Rods of length between 3 cm and 4 cm } & \quad & \color{orange} \text {Orange } \end{array} $

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?

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?

Whose Tail Is The Longest?

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

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

Whose Tail is the Longest?

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.

At the market

1) How many paise does a matchbox cost? ______

2) How many matchboxes can be got for ₹ 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.

5 a) 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?

Can I buy two pens with rupees 13?

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

Practice Time - Match These

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

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?

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

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 hte 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.

Sports Day

The school at Malappuram has its sports day.

The first five children in th Long Jump are:

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

Write in Metres

$ \begin{array}{lll} \text{ 3 metre 45 centimetre} & \begin{array}{|l|} \hline \hspace{ 1 cm} \\ \hline \end{array} & \text{ metres} \\ \\ \text{ 99 centimetre} & \begin{array}{|l|} \hline \hspace{ 1 cm} \\ \hline \end{array} & \text{ metres} \\ \\ \text{ 1 metre and 5 centimetre} & \begin{array}{|l|} \hline \hspace{ 1 cm} \\ \hline \end{array} & \text{ metres} \\ \\ \end{array} $

How Big Can You Get

Difference in size $\begin{array}{|l|} \hline \hspace{ 1 cm} \\ \hline \end{array}$

Do this for yourself and find the difference.

B)

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

Practice Time

1) Currency 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.

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

A) The currency 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?

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 ₹ 4? For ₹ 400?

2. How many Hong Kong Dollars can she change for ₹ 508?

2) Kiran went shopping with ₹ 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.

3) Which City Is Cool?

Children can be encouraged to look at temperatures (in degree Celsius or °C) of different cities in the newspaper 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?

2) How much higher is the temperature in Mumbai from that in Srinagar?

3) How many degrees will the temperature need to rise for it to reach $40^\circ$ C in Thiruvananthapuram ? º

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 3 pm and 3 am in Chennai? In Bhopal?