• Always simplify as low as possible.
• Always convert to common units when working out.
• Remove units in final answer.

When it comes to IGCSE/GCSE Maths, can you calculate the ratio of two different units?

• E.g. 500p : £15
  - common unit ⟶ £5 : £15
  - simplify ⟶ £1 : £3
  - final answer ⟶ 1 : 3

• Involves 3 variables.
• These can be connected by a triangle.
• E.g. Pay ⟶  hours worked × rate per hour
  - P = H × R
  - H = P/R
  - R = P/H

• 1m = 100 cm
• 1m² = 10,000cm (100 × 100)
• 1m³ = 1,000,000 cm³  (100 × 100 ×100)
   
• 1cm² = 100mm²
• 1m² = 10,000 cm²
• 1km² = 1,000,000 m²
   
• 1cm³ = 1,000 mm³
• 1m³ = 1,000,000 cm³
• 1km³ = 10⁹ m³

• If you go down a unit --> multiplication ×.
• If you go up --> division ÷.

That's the end of the topic!

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Drafted by Bonnie (Mathematics)