NCERT Solutions for Class 4th Maths Chapter 6 Metre and Centimetres — Let Us Do

Book page 90 Updated on2026-09-19

Q1.
The Village Sarpanch got the depth of some wells in his village measured by two different people. a) Fill the blanks such that the depths are the same. i) 2 m = 200 cm ii) __ m = 400 cm iii) 6 m = ____cm iv) __ m = 800m
Answer

The rule we use every time is 1 m = 100 cm.

i) 2 m = 100 + 100 = 200 cm   (done for us)

ii) 100, 200, 300, 400 → that is 100 counted 4 times
So 4 m = 400 cm

iii) 6 m = 100 + 100 + 100 + 100 + 100 + 100 = 600 cm

iv) 100, 200, 300, 400, 500, 600, 700, 800 → 100 counted 8 times
So 8 m = 800 cm
Depth in metresSame depth in centimetres
2 m200 cm
4 m400 cm
6 m600 cm
8 m800 cm
Why it happens: Each metre is 100 centimetres. So to go from metres to centimetres we add 100 once for every metre — the same as skip-counting in hundreds.
Note about a printing mistake in the book: part (iv) of the English book is printed as “__ m = 800m”. It should read 800 cm, and the Hindi book prints it correctly as 800 से.मी. Read it as 800 cm, so the answer is 8 m.
Q2.
b) Identify the wells with the same depth and match them.
Answer

Change every depth written in m and cm into plain centimetres, then look for the matching number.

1 m 40 cm = 100 + 40 = 140 cm
4 m 60 cm = 400 + 60 = 460 cm
2 m 30 cm = 200 + 30 = 230 cm
5 m 50 cm = 500 + 50 = 550 cm
Well measured by the first personMatches Well measured by the second person
1 m 40 cm140 cm
4 m 60 cm460 cm
2 m 30 cm230 cm
5 m 50 cm550 cm
Why it happens: Two people measured the same well but wrote the answer in different units. Once both are in centimetres, the equal ones are easy to spot.
Tip: Going the other way is just as easy. The hundreds become the metres: 460 cm = 4 m 60 cm.
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