Page 119 - Start Up Mathematics_3

2. Convert into centimetres.

(a) 9 m 99 cm (b) 15 m 47 cm (c) 4 m 75 cm (d) 9 m 22 cm

(e) 19 m (f) 12 m 80 cm (g) 450 m (h) 197 m 05 cm

3. Convert into metres and centimetres.
(a) 179 cm (b) 860 cm (c) 900 cm (d) 7791 cm

(e) 621 cm (f) 285 cm (g) 3871 cm (h) 1233 cm

Measuring length in kilometres

Longer lengths like the distance between two cities, the length of a river, height of
tall buildings and mountains, etc. cannot be measured in metres. So we use a bigger
unit of measurement called kilometre to measure such lengths.

Conversion of kilometres into metres Quick Tip

To convert km into m,
1 kilometre = 1000 metres or 1 km = 1000 m put three zeros to the

To convert a length given in kilometres into metres, right of the number.
we multiply by 1000. For example,

2 km = (2 × 1000) m = 2000 m
Mental Maths
12 km = (12 × 1000) m = 12000 m

Example 5: Convert 5 km 120 m into metres. 1 km = _________ cm

Solution: 5 km = 5 × 1000 m = 5000 m

5 km 120 m = 5000 m + 120 m = 5120 m

Conversion of metres into kilometres

We can convert metres into kilometres by dividing by 1000. For example,
7000 m = (7000 ÷ 1000) km = 7 km

10000 m = (10000 ÷ 1000) km = 10 km

Example 6: The distance between two cities A and B is 3252 m. Express this distance
in km and m.

Solution: 3252 m = 3000 m + 252 m

= 3 km + 252 m

= 3 km 252 m

Thus, the distance between city A and B is 3 km 252 m.

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