Page 98 - Math Skill - 4

96 Maths

The higher units of length are: The smaller units of length are:

1 Kilometre = 1000 metres 10 mm = 1 cm (centimetre)

1 Hectometre = 100 metres 10 cm = 1 dm (decimetre)
1 Decametre = 10 metres 10 dm = 1 m (metre)

Hence, 1 m = 10 dm = 100 cm = 1000 mm.

Converting Higher Units of length to Lower Units and Vice-Versa

To convert higher units to lower units, we multiply the higher unit by 10 for each step as
illustrated here:

× 10 × 10 × 10 × 10 × 10 × 10
km hm dam m dm cm mm

To convert lower units to higher units, we divide the lower unit by 10.

÷ 10 ÷ 10 ÷ 10 ÷ 10 ÷ 10 ÷ 10
km hm dam m dm cm mm

Let us learn through examples.

Let’s Attempt

Example 1: Convert 17 km into metres.

Solution: Since, 1 km = 1000 m
Thus, 17 km = (17 × 1000) m = 17000 m
Example 2: Convert 19 cm into mm.

Solution: Since, 1 cm = 10 mm
Thus, 19 cm = (19 × 10) mm = 190 mm

Example 3: Convert 23 km 25 m into m.
Solution: 23 km 25 m = (23 × 1000) m + 25 m [1 km = 1000 m]
= 23000 m + 25 m = 23025 m

Example 4: Convert 15 m 75 cm into cm.
Solution: 15 m 75 cm = (15 × 100) cm + 75 cm [1 m = 100 cm]

= 1500 cm + 75 cm = 1575 cm
Example 5: Convert 28 cm 8 mm into mm.
Solution: 28 cm 8 mm = (28 × 10) mm + 8 mm [1 cm = 10 mm]

= 280 mm + 8 mm = 288 mm
Example 6: Convert 12506 m into km and m.

Solution: 12506 m = (12000 + 506) m = 12000 m + 506 m
= (12000 ÷ 1000) km + 506 m  1 m = 1 km 


= 12 km + 506 m = 12 km 506 m  1000 