Percentage change questions are asking you to work out the difference in two different numbers as a percentage. Let’s take a look at what a percentage change question might look like:
Yesterday there were 160 sweets in a jar. Today there are 116, what is the percentage change?
To work this out we break it down into three steps.
Step 1: work out the difference in the two given numbers Step 2: Divide the difference by the starting number Step 3: Convert this into a percentage
If we apply this to our question,
First, we calculate the difference between 160 and 116, this gives us 44 Next, we divide 44 by 160 which equals 0.275
Finally, we multiply 0.275 by 100 to find what this number is as a percentage, leaving us with a 27.5% decrease
We know this is a percentage decrease because our starting number was 160 and our changed number was 116, which is a smaller number
If we started with 100 sweets and our changed number was 116 it would be an increase because the second number is bigger
So, there we have it, percentage change.