# Percent of a number

### Percent of a number

In this section, we will try to estimate the percent of a number without using a calculator. The trick is to breakdown the percent into smaller percent first. These smaller percentages are easier for mental calculation.

#### Lessons

• Introduction
a)
• What is a percent?
• How to find the percent of a number?

• 1.
Evaluate without using a calculator. Then, check your answers with a calculator.
a)
15% of 40

b)
320% of 600

c)
17.5% of 20

d)
$20\frac{1}{4}$% of 50

• 2.
The total rain precipitation of last summer was 350 mm. If it increased by $12\frac{1}{2}$% this summer, what was the rain precipitation this summer?