Practice question
Read the exemplar first
Illustrative: 12 of 40 seeds germinate. What percentage germinate?
(2)%
Total for this question: 2 marks
KS4 BIOLOGY · MATHS CLINICThe maths in Biology,
The maths in Biology,
at three levels.
10 skills that International GCSE Biology papers use. Each has a worked exemplar, then three different questions: Intro, Secure and Challenge. Answers are checked as you go, with the working. All numbers are illustrative.
You’ve done 0 of 30 · saved on this deviceKS4 Biology · Intro, then Secure, then Challenge.
N1 · Intro
Percentages and percentage change
Work out a percentage, and the percentage change between two values.
- Percentage = part ÷ whole × 100.
- Percentage change = (new − original) ÷ original × 100.
- A decrease gives a negative change.
Exemplar
Illustrative: a potato cylinder goes from 4.00 g to 4.60 g in water.
Change = 4.60 − 4.00 = 0.60 g. 0.60 ÷ 4.00 × 100 = +15%. Always divide by the original value.
Exam tip: For a percentage change, divide by the original (starting) value, not the new one.
Read the exemplar, then answer the Intro question. It is a different question. Full marks completes the level.