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!