⚖️ Ratio, Proportion & Rates

Compound interest

Learn compound interest with a GCSE-style explanation, help guide, worked example, practice question and flashcards.

Measures & MoneyGCSE25 XP completion3 flashcards

Global XP

Level 1

0 / 100 XP

1. Explanation

Key idea

Compound interest is part of measures & money and appears often in KS3–GCSE maths.
Compound interest applies interest to the new amount each period.
Use the worked model, help guide, interactive question and flashcards to practise compound interest until the steps feel automatic.

Shopping, sport, travel, science, design and everyday decisions all use this skill.

2. Visual

Understand the key idea → follow the help guide → practise a question → check your method → build speed with flashcards.

3. Help guide

Learn the rule: Compound interest applies interest to the new amount each period.
Worked model: Convert the percentage to a multiplier. Multiply once for each time period. Round money sensibly.
Try the interactive question without looking at the answer first.
Use the flashcards to test the rule, the method and a common check.

4. Worked examples

Answer: £200 at 5% for 2 years = £220.50

5. Interactive questions

6. Flashcards

Flip each card, then choose whether you know it or need more practice.

0 mastered

FrontRule for Compound interest

BackCompound interest applies interest to the new amount each period.

FrontExample answer: £100 grows by 10% compound interest for 2 years. What is it worth?

Back£100 × 1.10 × 1.10 = £121.

FrontCommon check for Compound interest

BackCheck units/notation, compare with an estimate, and make sure the answer matches the question.

7. Finish

When you have read the examples, tried the question and reviewed flashcards, claim your topic completion XP.