# What is 5% of 88.5cm?

Jan 1, 2017

Introduction to a way of thinking about numbers.

$4.425$

#### Explanation:

5% is just another way of writing $\frac{5}{100}$

So we have $\frac{5}{100} \text{ of "88.5" "->" } \frac{5}{100} \times 88.5$

This is the same as $5 \times \frac{88.5}{100} = 5 \times 0.885$

But 5 is $\frac{1}{2} \times 10$

So we can write $5 \times 0.885 \text{ as } \frac{1}{2} \times 10 \times 0.885$

$= \frac{1}{2} \times 8.85 = 4.425$