Multiplication of Decimals

We will discuss here about the multiplication of decimals. To multiply a decimal by a whole number, first we multiply as usual without considering decimal point. Then we put the decimal point in the product at the same place where it is placed in the given decimal.

Let us consider some of the following examples on multiplying decimals.

1. Multiply: 7.32 by 12.

  7  .  3  2

    ×  1  2

 1  4  6  4

 7  3  2  0

 8  7 . 8  4

The decimal point in decimal 7.32 is after two digits from the extreme right. So, we place the decimal point in the product just after two digits from the extreme right.

So, the product of 7.32 and 12 is 87.84.

2. Multiply the following:

(i) 12.345 by 8

1  2  .  3  4  5

              × 8

9  8  .  7  6  0

Decimals are multiplied in the same way as we multiply ordinary numbers. We place the digits in columns and then multiply as usual.

The decimal point in decimal 12.345 is after three digits from the extreme right. So, we place the decimal point in the product just after three digits from the extreme right.

So, the product of 12.345 and 8 is 98.760

(ii) 25.381 by 6

   2  5  .  3  8  1

                 × 6

1  5  2  .  2  8  6

The decimal point in decimal 25.381 is after three digits from the extreme right. So, we place the decimal point in the product just after three digits from the extreme right.

So, the product of 25.381 and 6 is 152.286.

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