Page 65 - Start Up Mathematics_4

To multiply a number by 20, 30, 40 and so on, write zero in the ones Working
place and then multiply the number by the remaining digit(s) and write 8 3
the product before zero. × 3

For example, 83 × 3 0 = 2,490 162 × 6 0 = 9,720 2 4 9

3 1
Multiplication by hundreds 1 6 2
× 6
To multiply a number by 100, write the number followed by two zeros. 9 7 2
For example, 90,472 × 100 = 90,47,200 4,816 × 100 = 4,81,600

To multiply a number by 200, 300, 400 and so on, write two zeros at the
end and then multiply the number by the remaining digit(s) and write Working
the product before the two zeros. 1 1
1 2 3
For example, 15 × 4 00 = 6,000 123 × 6 00 = 73,800 × 6
7 3 8
Multiplication by thousands
To multiply a number by 1,000, write the number followed by three zeros.

For example, 10,394 × 1,000 = 1,03,94,000 55,508 × 1,000 = 5,55,08,000

To multiply a number by 2,000, 3,000, 4,000 and so on, write three zeros Working
at the end and then multiply the number by the remaining digit(s) and 1
write the product before the three zeros. 4 8

For example, 48 × 2,000 = 96,000 513 × 5 ,000 = 25,65,000 × 2
9 6
A Challenge! 1
5 1 3
Complete the pattern. × 5
2 5 6 5
5 × = 30 5 × = 300

5 × = 3,000 5 × = 30,000

EXERCISE 5.3

1. Circle the correct answer.
(a) 54 × 10 = 504 540 5,400 5,040
(b) 98 × 100 = 980 908 9,800 9,080
(c) 70 × 1,000 = 70,000 7,000 700 7,00,000

(d) 231 × 100 = 2,300 2,31,000 23,100 23,010
(e) 450 × 10 = 450 45,000 4,050 4,500
(f) 926 × 1,000 = 92,600 9,26,000 9,260 9,20,600

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