Step by step
The question
Question: find the percent change from 50 to 60.
1 Find the change
First: how much did it change?
It went up from 50 to 60.
60 minus 50 is 10.
It went up, so it is an increase.
2 Compare with the start
Now we compare the change with where we started.
The change, 10, goes on top.
The old number, 50, goes on the bottom.
Careful: we divide by the number we started with, 50.
Not by the new number.
3 Make the bottom 100
Percent means out of 100.
So we want 100 at the bottom.
100 divided by 50 is 2.
So 50 times 2 is 100.
We multiply the top and the bottom by 2.
So the fraction keeps its size.
10 times 2 is 20.
50 times 2 is 100.
20 out of 100 is 20%.
So it is a 20% increase.
4 Check
Let's check: 20% of 50 should be the change, 10.
20% is 20/100.
Of means times.
To keep the numbers small, we divide the top and the bottom by 20.
20 goes into 100: 20 × 5 = 100.
So 20 goes into both.
That is 1/5.
50 divided by 5 is 10.
That is 10.
And 50 plus 10 is 60, the new number.
So it is right!
Let's look back.
First: find the change.
Then: compare with the start.
Then: make the bottom 100.
Last: check.