Edexcel IGCSE Maths topic guide

Number

Number skills appear throughout both Foundation and Higher papers. Accurate arithmetic, clear units and sensible rounding often support marks in algebra, geometry and statistics as well as in dedicated Number questions.

Foundation and Higher relevance

Core content for Foundation and Higher. Higher papers place greater emphasis on exact values, bounds, surds and multi-step proportional reasoning.

Topic coverage

Integers, place value and order of operations
Factors, multiples and prime factorisation
Fractions, decimals and percentages
Ratio and direct or inverse proportion
Standard form
Rounding, estimation and limits of accuracy
Repeated percentage change
Indices and powers
Surds and exact values
Set notation and Venn diagrams

Worked example

Question: A value increases by 12% and then decreases by 12%. Is the final value unchanged?

Represent the original value by 100.
Increase it using the multiplier 1.12: 100 × 1.12 = 112.
Apply the decrease to the new value: 112 × 0.88 = 98.56.

Answer: No. The final value is 98.56, so it is 1.44% below the original value.

Common errors

Adding or subtracting percentages instead of using multipliers for repeated change.
Rounding during intermediate steps and losing accuracy in the final answer.
Giving a decimal when an exact fraction or surd is required.

Revision checklist

I can move between fractions, decimals and percentages.
I can use upper and lower bounds in a calculation.
I can simplify indices, standard form and surds without a calculator.