Lesson 13- Multiplying Decimals by Whole Numbers

Objectives:

At the end of this lesson, students should be able to multiply decimals by whole numbers.

Multiplying means continues addition. It implies adding a particular number to itself a number of times. The same rule applies when multiplying decimals by whole numbers.

Consider the number line below.

The number line shows four (4) jumps in steps of 0.3 each time. This ends on 1.2. It implies that 0.3 + 0.3 + 0.3 + 0.3 = 1.2

Using multiplication, we can say that:

0.3 x 4 = 1.2

Workout:

0.3

X  4

1.2

Here it is evident that multiplication of decimals follows the normal method of multiplication except that the answer bears the same number of decimal places as the decimals being multiplied.

Example 1

a. 4.8 x 3             b.  2.65 x 6      c.  1.293 x 8              d.  13.4 x

Solution

                           

Example 2

Complete the multiplications below.

a. 0.64 x 12                       b.  2.389 x 23