Lesson 14- Multiplying Decimals by Multiples of 10 or 100

Objective

At the end of this lesson, students should be able to multiply decimals by multiples of 10 or 100.

Decimals can easily be multiplied by multiples of 10 or 100.

Example 1

a. 1.52 x 20                             b.  4.671 x 50

Solution

a. 1.52 x 20

(20 = 10 x 2)

First multiply the decimal by 10, and then multiply your answer by 2.

a. 5x 10 = 15.2

Therefore, 1.52 x 20 = 30.4

b. 4.671 x 50

4.671 x 50 = 4.671 x (10 x 5)

                   = (4.671 x 10) x 5

                 = 46.71 x 5

Example 2

a. 3.64 x 400                             b.  7.805 x 800

Solution