Theory
With percentage increase, you look at how much has been added.
You always compare that increase with the starting value, because the starting value is 100%.
Divide the increase by the starting value and then multiply by 100.
- Calculate how much has been addedSubtract the starting value from the new value.
When subtracting, you take away an amount or calculate the difference between two numbers.
The first number is the starting number. The second number is what you subtract from it.
Pay attention to whether you cross a ten. Then you need to carefully keep track of the ones and tens separately.
- Compare the increase with the starting valueUse the increase as the part and the starting value as the whole.
A percentage compares a part with a whole, where the whole is 100%.
Divide the part by the whole to see what part of the total you have.
Then multiply by 100 and put a percent sign after it.
- Divide by the wholeDivide the part by the whole to see what part of the whole you have.
Dividing means sharing an amount fairly or seeing how many equal groups fit into it.
The first number is the total amount. The second number tells you what you divide by.
Always check whether the division works out exactly. If it does not, you get a decimal number or fraction as the answer.
- Convert to percentMultiply by 100 to write the part as a percentage.
You use multiplication with equal groups.
A × B means that you take the same amount B, A times.Instead of adding again and again, you calculate the product all at once.
- Divide by the whole
- Calculate how much has been added50 - 40 = 10.
- Compare the increase with the starting valueCompare the increase 10 with the starting value 40.
- Divide by the whole10 ÷ 40 = 0,25.
- Convert to percent0,25 × 100 = 25%.
- Divide by the whole