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NCERT Solutions for Class 5th Maths Chapter 5 Word problems on adding and subtracting lengths — Let Us Do

Book page 66 Updated on2026-09-19

Q1.
Rani has two red-coloured ribbon rolls, one of length 3 m 75 cm and another 2 m 25 cm long. How much ribbon does she have?
Answer

Rani has 6 m of ribbon.

We must find the total length, so we add the two rolls.

  1. Add the metres. 3 m + 2 m = 5 m.
  2. Add the centimetres. 75 cm + 25 cm = 100 cm.
  3. 100 cm is a whole metre, so change it: 100 cm = 1 m.
  4. Join them. 5 m + 1 m = 6 m.
3 m 75 cm + 2 m 25 cm
= 5 m + 100 cm
= 5 m + 1 m
= 6 m of ribbon
Check it the other way: 3 m 75 cm = 375 cm and 2 m 25 cm = 225 cm. 375 + 225 = 600 cm = 6 m ✓
Why the answer is so neat: 75 and 25 are partners that make 100. Look for such pairs — 40 and 60, 30 and 70, 90 and 10 — they turn a messy addition into an easy one.
Q2.
The distance from Bhopal to Sanchi is 48 km 700 m. Bhadbhada Ghat waterfall is on the way, and 17 km 900 m away from Bhopal. How far is Sanchi from the waterfall?
Answer

Sanchi is 30 km 800 m from the waterfall.

Name the quantities first. Bhopal, the waterfall and Sanchi lie on one road, in that order.

BhopalBhadbhada GhatSanchi 17 km 900 m ? 30 km 800 m Whole road Bhopal → Sanchi = 48 km 700 m
The waterfall is on the way, so the two smaller pieces make up the whole road.
  1. Change both distances into metres. 48 km 700 m = 48,700 m. 17 km 900 m = 17,900 m.
  2. Subtract, because we want the leftover piece of road. 48,700 − 17,900 = 30,800 m.
  3. Change back. 30,800 m = 30,000 + 800 = 30 km 800 m.
  48,700 m
− 17,900 m
—————————————
  30,800 m = 30 km 800 m
Check it yourself: 17 km 900 m + 30 km 800 m = 47 km 1,700 m = 48 km 700 m ✓ That is the full Bhopal–Sanchi road.
Did you know? Sanchi in Madhya Pradesh has the Great Stupa, built more than two thousand years ago in the time of Emperor Ashoka.
Q3.
Gulmarg Gondola in Gulmarg, Kashmir is the second longest and second highest cable car in the world. It is divided into two sections. The first section covers 2 km 300 m and the second section covers 2 km 650 m. What is the total distance covered by the cable car?
Answer

The cable car covers 4 km 950 m in all.

We want the total, so we add the two sections.

  1. Add the kilometres. 2 km + 2 km = 4 km.
  2. Add the metres. 300 m + 650 m = 950 m.
  3. 950 m is less than 1,000 m, so it stays as it is. No carrying needed.
2 km 300 m + 2 km 650 m
= 4 km 950 m
= 4 km 950 m  (= 4,950 m)
Why nothing was carried here: A kilometre is only made when the metres reach 1,000. Here they reached only 950, which is 50 short. So the metres stay in the metre place.
Check it yourself: 2,300 m + 2,650 m = 4,950 m ✓ And 4,950 m = 4 km 950 m.
Q4.
Circle the bigger length and find the difference. (a) 11 mm and 1 cm (b) 26 mm and 2 cm (c) 20 cm and 201 mm (d) 1,020 mm and 1 m (e) 2 m and 245 cm (f) 5,678 m and 6 km (g) 6 km 1,480 m and 7 km 479 m
Answer

The one rule: change both lengths into the same unit first, then compare and subtract.

PartBoth in one unitBigger length (circle this)Difference
(a) 11 mm and 1 cm11 mm and 10 mm11 mm1 mm
(b) 26 mm and 2 cm26 mm and 20 mm26 mm6 mm
(c) 20 cm and 201 mm200 mm and 201 mm201 mm1 mm
(d) 1,020 mm and 1 m1,020 mm and 1,000 mm1,020 mm20 mm = 2 cm
(e) 2 m and 245 cm200 cm and 245 cm245 cm45 cm
(f) 5,678 m and 6 km5,678 m and 6,000 m6 km322 m
(g) 6 km 1,480 m and 7 km 479 m7,480 m and 7,479 m6 km 1,480 m1 m

The working, one part at a time.

(a) 1 cm = 10 mm. 11 − 10 = 1 mm
(b) 2 cm = 20 mm. 26 − 20 = 6 mm
(c) 20 cm = 200 mm. 201 − 200 = 1 mm
(d) 1 m = 1,000 mm. 1,020 − 1,000 = 20 mm, which is 2 cm
(e) 2 m = 200 cm. 245 − 200 = 45 cm
(f) 6 km = 6,000 m. 6,000 − 5,678 = 322 m
(g) 6 km 1,480 m = 6,000 + 1,480 = 7,480 m
    7 km 479 m = 7,000 + 479 = 7,479 m
    7,480 − 7,479 = 1 m
Part (g) is the tricky one. At first glance 7 km 479 m looks bigger, because 7 is bigger than 6. But 6 km 1,480 m has 1,480 metres in it — more than a whole kilometre extra. Once you change both into metres the trap disappears: 7,480 m against 7,479 m. Never compare only the first number.
Tip: Parts (a) and (c) show how close two lengths can be — just 1 mm apart. That is why millimetre marks matter on a ruler.
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