Percentages help us calculate changes in value, whether it's depreciation...
Maths390 views·Updated Jun 15, 2026·2 pagesUnderstanding Percentages
A
Abi Thomson@abithomson_hose
1
of 2
Calculating Depreciation with Percentages
When an item loses value over time, we call it depreciation. To calculate the amount lost, multiply the original value by the depreciation percentage as a decimal. For example, with a car worth £9,550 that depreciates by 30%, we convert 30% to 0.3 and multiply: 0.3 × £9,550 = £2,865 depreciation.
To find the new value after depreciation, you have two methods. You can subtract the depreciated amount from the original price: £9,550 - £2,865 = £6,685. Alternatively, recognize that after a 30% decrease, the car is worth 70% of its original value, so calculate: 0.7 × £9,550 = £6,685.
💡 Remember this shortcut: If something decreases by X%, its new value is % of the original. For a 30% decrease, multiply by 0.7 to find the new value directly.
2
of 2
Calculating Appreciation and Depreciation
When property values increase, we call it appreciation. For a house bought for £87,500 that appreciates by 9% over time, we find the new value by multiplying the original amount by 1.09 (adding the percentage increase to 100%): £87,500 × 1.09 = £95,375.
Calculating depreciation follows similar logic. If a flat bought for £120,000 depreciates by 3% after two years, we find its new value by multiplying the original amount by 0.97 (100% - 3%): £120,000 × 0.97 = £116,400.
💡 Quick tip: For increases, add the percentage to 100% (as a decimal). For a 9% increase, multiply by 1.09. For decreases, subtract the percentage from 100%. For a 3% decrease, multiply by 0.97.
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Maths390 views·Updated Jun 15, 2026·2 pagesUnderstanding Percentages
A
Abi Thomson@abithomson_hose
Percentages help us calculate changes in value, whether it's depreciation (decrease) or appreciation (increase). This summary covers how to work out these changes step-by-step using simple multiplication methods.
1
of 2
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Calculating Depreciation with Percentages
When an item loses value over time, we call it depreciation. To calculate the amount lost, multiply the original value by the depreciation percentage as a decimal. For example, with a car worth £9,550 that depreciates by 30%, we convert 30% to 0.3 and multiply: 0.3 × £9,550 = £2,865 depreciation.
To find the new value after depreciation, you have two methods. You can subtract the depreciated amount from the original price: £9,550 - £2,865 = £6,685. Alternatively, recognize that after a 30% decrease, the car is worth 70% of its original value, so calculate: 0.7 × £9,550 = £6,685.
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2
of 2Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
Calculating Appreciation and Depreciation
When property values increase, we call it appreciation. For a house bought for £87,500 that appreciates by 9% over time, we find the new value by multiplying the original amount by 1.09 (adding the percentage increase to 100%): £87,500 × 1.09 = £95,375.
Calculating depreciation follows similar logic. If a flat bought for £120,000 depreciates by 3% after two years, we find its new value by multiplying the original amount by 0.97 (100% - 3%): £120,000 × 0.97 = £116,400.
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