Page 34 - Start Up Mathematics_5

Step 2: Multiply 1,56,45,680 by 306.

Carry over of → 1 1 1 1 2 2 Carry over of

(1,56,45,680 × 300) 3 3 2 3 4 4 → (16,45,680 × 6)

1 5 6 4 5 6 8 0
× 3 0 6

1

1 9 3 8 7 4 0 8 0 → (1,56,45,680 × 6)

+ 4 6 9 3 7 0 4 0 0 0 → (1,56,45,680 × 300)

4 7 8 7 5 7 8 0 8 0

Quick Tip Mental Maths
Note that while multiplying Choose 2 numbers from the box
by 306, we have not shown whose product is 108 and write in
the multiplication by 0 as the empty boxes. × = 108
it is not required.
12 6 8
14 7 18

EXERCISE 2.4

1. Multiply using multiplication tables and verify your result by actual multiplication.

(a) 64 × 13 (b) 81 × 15 (c) 321 × 16 (d) 259 × 17
(e) 1,307 × 18 (f) 2,045 × 19 (g) 49 × 18 (h) 172 × 17
(i) 650 × 15 (j) 86 × 19 (k) 234 × 14 (l) 8,215 × 16

2. Find the following products.
(a) 16,305 × 248 (b) 3,09,154 × 627 (c) 5,23,614 × 908 (d) 4,855 × 3,126

(e) 21,739 × 4,085 (f) 9,541 × 382 × 75 (g) 9,132 × 87 (h) 34,862 × 195
(i) 28,065 × 204 (j) 5,416 × 98 (k) 79,843 × 621 (l) 90,276 × 85

Multiplication by 10 and its multiples Mental Maths

• To multiply a number by 10, write the number followed by Find the product.
a zero. (a) 9,82,674 × 10
• To multiply a number by a multiple of 10, write zero in the (b) 11,311 × 50
ones place and then multiply the number by the remaining (c) 8,00,512 × 20
digit(s) and write their product before zero. (d) 11,11,11,111 × 90

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