Percentages (Edexcel GCSE Maths): Flashcards

Divide by 100

Convert % to decimal, then multiply by y

$1 - 0.4 = 0.6$

$1 + 0.15 = 1.15$

Divide x by y, multiply by 100

$\frac{\text{Change}}{\text{Original}} \times 100$

Always the original value, not final value

Identify %, divide by %, find 1%, multiply by 100

Never 100% - always more or less than 100%

Same amount earned each period, calculated on original only

Calculate interest for 1 period, multiply by number of periods

Must be the same/consistent throughout

Original cost price, not selling price

$120\%$ of original ($100\% + 20\%$)