How Can You Calculate Percentages?
Here you will learn about the calculation of percentages. It is often useful to know how to convert numbers to percentages and back. For example, you have probably been shopping while there has been a sale. How much will something cost if you get a 40 % discount? How do you calculate that? That is exactly what we are going to look at here.
When you want to find the percentage of a number:
Calculate 40% of 300.
This means 40% of 300 is 120.
Find 75% of 80.
80 ⋅ 75% = 80 ⋅ 75 100 = 80 ⋅ 75 100 = 8 ⋅ 75 10 = 8 ⋅ 7.5 = 60 This means 75% of 80 is 60.
What should you do if you want to add a percentage? I will show you how with two methods: The long way and the short way. The short method uses a growth factor, and you will find that it becomes your best friend. Let us try an example.
You want to add 15% to 400.
You are out shopping during a sale. You find a jacket with a discount that says 30% off. The regular price is $70. How much do you have to pay?
We’re going to use the growth factor method: