Percentages of Amounts
Master percentages of amounts for GCSE Maths with structured, exam-style practice. This Foundation and Higher resource covers finding percentages of an amount and includes a complete mark scheme showing the steps examiners reward. Suitable for AQA, Edexcel and OCR. Free to download as a PDF. Find 10% by dividing by 10, then build up the percentage you need.
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These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA, Edexcel and OCR specifications. Every worksheet comes with a full mark scheme.
Topic overview
Finding a percentage of an amount is one of the most useful skills in the whole GCSE, because it underpins interest, discounts, VAT, wages and almost every real-life money question.
There are two reliable methods. The non-calculator approach builds the percentage from parts you can find easily, such as 10 percent, 5 percent and 1 percent. The calculator approach uses a multiplier: convert the percentage to a decimal and multiply once.
Both give the same answer, so choose the one that suits the question. Foundation papers often want the building-block method shown clearly, while Higher papers usually reward the faster multiplier approach, especially when several percentage steps follow one another.
Revision notes
The building-block method
Start from 10 percent, which is the amount divided by 10. From there, 5 percent is half of 10 percent and 1 percent is the amount divided by 100.
To find 35 percent of \(£80\): 10 percent is \(£8\), so 30 percent is \(£24\); 5 percent is \(£4\); adding gives \(£28\). Showing these parts earns method marks even if the final addition slips.
The multiplier method
Divide the percentage by 100 to get a decimal, then multiply. For 35 percent the multiplier is \(0.35\), so \(0.35 \times 80 = 28\).
This is far quicker for awkward percentages such as 17.5 percent or 3 percent, and it is essential once you meet repeated percentage change, where you multiply by the same number several times.
Increases and decreases
To increase by a percentage, add it to 100 percent before converting. A 20 percent increase uses a multiplier of \(1.2\); a 20 percent decrease uses \(0.8\).
This single step replaces finding the percentage and then adding or subtracting it, and it is much less error-prone in multi-stage questions.
Key points
- 10 percent is the amount divided by 10.
- 1 percent is the amount divided by 100.
- The multiplier is the percentage divided by 100.
- To increase by \(p\) percent, multiply by \(1 + \frac{p}{100}\).
- To decrease by \(p\) percent, multiply by \(1 - \frac{p}{100}\).
- Both methods give the same answer, so pick whichever suits the numbers.
Worked examples
Example 1
Find 15 percent of \(£240\) without a calculator.
Working
Example 2
Use a multiplier to find 68 percent of \(£350\).
Working
Example 3
A coat costs \(£64\) and is reduced by 25 percent. Find the sale price.
Working
Common mistakes
Using 0.5 as the multiplier for 5 percent.
5 percent is 5 ÷ 100 = 0.05. Using 0.5 finds 50 percent instead, ten times too much.
Finding the decrease but forgetting to subtract it.
If a question asks for the sale price, the percentage found must still be taken off the original amount, unless you used the 0.75-style multiplier.
Adding percentages of different amounts together.
10 percent of £50 and 10 percent of £80 are not the same, so the parts must come from the same starting amount.
Rounding money to more than 2 decimal places.
Money answers should be given to the nearest penny, so £23.456 is written as £23.46.
Exam tips
- Show the 10 percent and 1 percent steps in non-calculator questions to secure method marks.
- Use a single multiplier when a percentage change is applied more than once.
- Write money answers to 2 decimal places with the pound sign.
- Check the direction of the answer: an increase must be larger than the original.
Key terms
- Percentage
- A proportion expressed out of 100.
- Multiplier
- The decimal you multiply by to apply a percentage, such as 0.85 for a 15 percent decrease.
- Percentage increase
- Adding a proportion of the original amount to itself.
- Original amount
- The starting value before any percentage change is applied.
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Written and reviewed against the current AQA, Edexcel and OCR specifications. Spotted an error? Let us know.