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Number Revision

Fractions, decimals & percentages — part of Maths on KODO.

AQA Edexcel OCR WJEC SQA

Number is a core area of KS3 Maths in the national curriculum. It covers essential concepts that build the foundation for GCSE study and beyond.

This topic includes subtopics such as Fractions, Decimals, Percentages, Ratios and more. Each area is tested with multiple-choice questions that include detailed explanations to deepen your understanding.

Quick Reference

First 10 primes2, 3, 5, 7, 11, 13, 17, 19, 23, 29
HCF of 12 and 186
LCM of 4 and 612
25% of 8020 (80 ÷ 4)

Key Definitions

Prime number
A number greater than 1 that has exactly two factors: 1 and itself (e.g. 2, 3, 5, 7).
HCF
Highest Common Factor — the largest number that divides exactly into two or more numbers.
LCM
Lowest Common Multiple — the smallest number that is a multiple of two or more numbers.
Percentage
A proportion out of 100. To find 10%, divide by 10.
Reciprocal
1 divided by the number. The reciprocal of 5 is 1/5.

What You'll Cover

Fractions
Decimals
Percentages
Ratios
Primes/Factors
BIDMAS
Fractions, decimals and percentages
Ratio and proportion
Order of operations (BIDMAS)
Powers and roots
Negative numbers

Test Yourself — Number

Try 3 quick questions. No account needed.

Quick Quiz

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Memory Tricks & Mnemonics

"Divide, Multiply, Subtract, Bring down" (DMSB) for long division

Remember the steps of the bus-stop method.

"King Henry Doesn't Mind Drinking Chocolate Milk" (Kilo, Hecto, Deca, Main, Deci, Centi, Milli)

Convert between metric units by moving the decimal point.

To find a percentage of a number: divide by 100, multiply by the %

Quick percentage calculations in your head.

Frequently Asked Questions

What is Prime number in Maths?+
A number greater than 1 that has exactly two factors: 1 and itself (e.g. 2, 3, 5, 7).
What is HCF in Maths?+
Highest Common Factor — the largest number that divides exactly into two or more numbers.
What is LCM in Maths?+
Lowest Common Multiple — the smallest number that is a multiple of two or more numbers.
What is Percentage in Maths?+
A proportion out of 100. To find 10%, divide by 10.
What does Number cover in KS3 Maths?+
Number in KS3 Maths covers Fractions, Decimals, Percentages, Ratios, Primes/Factors, BIDMAS, Fractions, decimals and percentages, Ratio and proportion. Fractions, decimals & percentages.
What is the best way to revise Number?+
Test yourself rather than re-reading notes. Do a short Number quiz, read the explanation for every answer you get wrong, then come back to those questions a few days later. KODO does this automatically with spaced repetition, and you can turn any topic into printable flash cards.
Is Number revision on KODO free?+
Yes. KODO is free for everyone until Friday 18 December 2026, with unlimited quizzes on Number and every other topic. After that there is still a free plan with daily quizzes.

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More Maths Topics

AlgebraGeometryStatistics

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