Page 207 - New Medley 5 Semester 1

428 428
.
Also 4.28 × 10 = × 10 = = 42 8 ,
100 10
428
4.28 × 100 = × 100 = 428
100

428
and 4.28 × 1000 = × 1000 = 428 × 10 = 4280
100

Thus, we see that when a decimal is multiplied by 10, 100 and 1000, the

decimal point shifts 1, 2 and 3 places to its right in the product.
Multiplying a Decimal by a Decimal

We can multiply two decimals by following these steps:

Z Z Ignore the decimal points and multiply the numbers as usual.

Z Z Count the number of decimal places in the multiplier and multiplicand.
Add them.

Z Z Now, starting from the right, count as many digits in the product as many decimal
places mentioned in the decimal numbers and then insert the decimal point.

Example 11: Multiply 2.345 by 1.37.
Solution: 2.345 × 1.37 = ?

2 3 4 5
 2.345 × 1.37 = 3.21265
× 1 3 7

1 6 4 1 5 3 decimal 5 decimal
7 0 3 5 places places

2 3 4 5 2 decimal
places
3 2 1 2 6 5

Continued Product of Decimals

To find the product of more than two decimals like 6.2 × 3.5 × 1.6, multiply

any two first and then multiply this product with the third decimal.

Here, 6.2 × 3.5 × 1.6 = 21.70 × 1.6 = 34.720 or 34.72

or 6.2 × 3.5 × 1.6 = 6.2 × 5.60 = 34.720 or 34.72

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