Key Ratio Concepts

Part of Ratio Basics Ā· Section 3 of 15

Key FactsUnit: NumberGCSE
Concept Method Example Key Point
Simplifying Divide by HCF 6:8 = 3:4 Find highest common factor
Sharing Find total parts Share Ā£20 in 2:3 → 2+3=5 parts Each part = total Ć· parts
Scaling Multiply all parts 2:5 scaled by 3 = 6:15 Keep ratio the same
Three-way a:b:c format Red:Blue:Green = 2:3:5 Total parts = a+b+c
Equivalent Same when simplified 4:6 = 2:3 = 6:9 Multiply/divide both parts

This key facts covers Key Ratio Concepts within Ratio Basics for GCSE Mathematics. Revise Ratio Basics in Number for GCSE Mathematics with 12 exam-style questions and 22 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 3 of 15 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.

Practice questions for Ratio Basics

Write the ratio 12:18 in its simplest form.

  • A. 6:9
  • B. 4:6
  • C. 2:3
  • D. 3:2
1 markfoundation

Explain the difference between the ratio 3:5 and the ratio 5:3.

2 marksstandard

Quick recall flashcards

Order in Ratios
Order MATTERS! Boys:Girls = 3:5 means: • 3 boys for every 5 girls Girls:Boys = 5:3 means: • 5 girls for every 3 boys Different meanings!
What is a ratio?
A comparison of quantities of the same kind Written as a:b or a/b Example: 3:5 means '3 parts to 5 parts'

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