Metres and centimetres

In your book, Maths Mela (Chapter 6), Ramu and Shamu use a measuring tape to measure their height. Ramu reads it as 120 cm. Shamu reads it as 1 m 20 cm. Who is correct? Pinki says both are! She shows that 120 cm is 100 cm and 20 cm more. 100 cm is 1 m, so 120 cm = 1 m 20 cm.

To change metres into centimetres, remember that every metre is 100 cm. 2 m = 200 cm, 4 m = 400 cm, 6 m = 600 cm, and 8 m = 800 cm. The Village Sarpanch has the depths of some wells measured, one person in m and cm and another in cm only. 4 m 60 cm is 400 cm + 60 cm = 460 cm. 1 m 40 cm is 140 cm, 2 m 30 cm is 230 cm, and 5 m 50 cm is 550 cm.

To go back the other way, take out each 100 cm as 1 m. 460 cm is 400 cm and 60 cm, which is 4 m 60 cm.

The book also asks: Sonu has a board 2 metres long and border stickers 20 cm long. How many stickers cover the board? First change 2 m into 200 cm. Then count in twenties: 20, 40, 60, 80, 100 is 5 stickers for 1 m, and 5 more for the next metre. So Sonu needs 10 stickers.