Year 10 - Maths
Percentage profit and loss
Percentages
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
In this unit pupils will learn how to perform simple and compound interest calculations using percentages.
Lesson Summary
You will learn to calculate percentage profit and percentage loss.
Key Notes
- When calculating percentage profit or loss, you are interested in the change.
- If the final amount is more than the original, there is profit.
- If the final amount is less than the original, there is loss.
- This change can be described as a percentage of the original amount.
- A negative percentage is interpreted as a loss.
Vocabulary To Learn
- Percentage profit: is the increase when referencing something that is sold for more than the cost price given as a percentage of the original amount
- Percentage loss: is the decrease when referencing something that is sold for less than the cost price given as a percentage of the original amount
Common Mistakes To Avoid
- When using multipliers, pupils can mistake a decimal for the percentage decrease. e.g. 0.52 is a 52% decrease, rather than recognising a 48% decrease
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
When calculating percentage profit or loss, you are interested in the change. If the final amount is more than the original, there is profit.
2. Use this key word in a maths sentence and explain it clearly. 'Percentage profit'
is the increase when referencing something that is sold for more than the cost price given as a percentage of the original amount. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: When using multipliers, pupils can mistake a decimal for the percentage decrease. e.g. 0.52 is a 52% decrease, rather than recognising a 48% decrease. Correction: Reminding students that a decimal multiplier greater than 1 means an increase, and a decimal multiplier less than 1 means a decrease. The latter requires a subtraction from 1 or 100%.
More Lessons In This Unit
- Advanced problem solving with percentages Study Guide
- Calculating compound interest rates Study Guide
- Changing compound interest rates Study Guide
- Checking and securing understanding of finding a percentage Study Guide
- Checking and securing understanding of percentage decrease Study Guide
- Checking and securing understanding of percentage increase Study Guide
- Compound interest calculations Study Guide
- Compound interest calculations with technology Study Guide
- Problem solving with percentages Study Guide
- Simple and compound interest Study Guide
- Simple interest calculations Study Guide
- Simple interest calculations with technology Study Guide
Browse all guides in the Year 10 Maths guide library.