Page 156 - New Medley 4 Semester 1

Multiplying by 10, 100, 1000 and 10000

Z Z To multiply a number by 10 put one zero to the right of the number.
Z 6293 × 10 = 62930, 7397 × 10 = 73970, 6486 × 10 = 64860

Z Z To multiply a number by 100 put two zeros to the right of the number.
Z 729 × 100 = 72900, 718 × 100 = 71800, 845 × 100 = 84500

Z Z To multiply a number by 1000 put three zeros to the right of the number.

Z 84 × 1000 = 84000, 29 × 1000 = 29000, 37 × 1000 = 37000

Z Z To multiply a number by 10000 put four zeros to the right of the number.

Z 9 × 10000 = 90000, 6 × 10000 = 60000, 8 × 10000 = 80000

EXERCISE 3.4

Multiply.
1. 28423 × 10 2. 36243 × 10 3. 4263 × 100

4. 8633 × 100 5. 989 × 1000 6. 691 × 1000

7. 765 × 10000 8. 341 × 10000 9. 43 × 100000

Multiplication by Multiples of 10

Example 4: Multiply.

(a) 14232 by 20 (b) 1318 by 300 (c) 2146 by 2000

Solution: (a) 14232 × 20 =

To multiply a number by 20 we multiply it by 2 and put
a zero after it.

14232 × 2 = 28464

So the product is 284640. (We put a zero after 28464)

(b) 1318 × 300 =
To multiply a number by 300 we multiply it by 3 and

put a two zeros after it.

1318 × 3 = 3954

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