In this activity, we will learn how to calculate percentages of numbers without using a calculator.

 

To find 10% of a number, we simply find one tenth, or divide by ten.

 

Look at these examples:

10% of 300 = 300 ÷ 10 = 30

10% of 55 = 55 ÷ 10 = 5.5

10% of 120 = 120 ÷ 10 = 12

 

We can then use this fact to work out larger percentages which are multiples of 10. 

For example, if we know that 10% of 200 is 20, we can find 20% or 30% easily using multiplication.

 

10% of 200 = 20 (200 ÷ 10)

20% of 200 = 40 (20 × 2)

30% of 200 = 60 (20 × 3)

 

Let's try an example together.

 

Example

Find 40% of 240.

 

Answer

First, we find 10% of 240 by dividing 240 by 10.

240 ÷ 10 = 24

 

Next, we multiply this by 4 to get 40% of 240.

24 x 4 = 96

 

Happy with that?

 

 

Now it's time to try some of these yourself. 

Best of luck!