NCERT Solutions for Class 4th Maths Chapter 9 Breaking the number of groups into tens — Multiplying Using 10s

Book page 138 Updated on2026-09-19

Q1.
Radha is packing cupcakes in boxes of 4. She has packed 18 boxes. How many cupcakes are there in the packed boxes? 10 boxes with 4 cupcakes in each contain 10 × 4 cupcakes = ______ cupcakes. 8 boxes with 4 cupcakes in each contain 8 × 4 cupcakes = ______ cupcakes. 18 boxes with 4 cupcakes in each contain ____ + ____ cupcakes = ______ cupcakes.
Answer
10 boxes with 4 cupcakes in each.
8 more boxes with 4 cupcakes in each.

There are 72 cupcakes in the 18 boxes.

18 boxes = 10 boxes + 8 boxes
10 boxes: 10 × 4 = 40 cupcakes
8 boxes: 8 × 4 = 32 cupcakes
18 boxes: 40 + 32 = 72 cupcakes
×4
1010 × 4 = 40
88 × 4 = 32
72

The same work written in the book’s table.

Why it happens: 18 boxes can be split into a friendly group of 10 and a group of 8. Nothing is lost, so the two parts are added back together.
Q2.
8 bamboo rods are needed to make a bullock cart. How many bamboo rods are needed for 23 carts? 20 carts with 8 rods in each need 20 × 8 rods = ________ rods. 3 carts with 8 rods in each need 3 × 8 rods = _________ rods.
Answer
88888888888888888888
20 carts, 8 bamboo rods for each.
888
3 more carts, 8 bamboo rods for each.

184 bamboo rods are needed for 23 carts.

23 carts = 20 carts + 3 carts
20 carts: 20 × 8 = 160 rods
3 carts: 3 × 8 = 24 rods
23 carts: 160 + 24 = 184 rods
×8
2020 × 8 = 160
33 × 8 = 24
184

The same work written in the book’s table.

Tip: 20 × 8 is easy: 2 × 8 = 16, so 20 × 8 = 160.
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