GCSE Mathematics
GCSE Maths: Number Revision
Number revision for GCSE and iGCSE Maths
Number is the topic that quietly decides grades. It is not usually the hardest content on the paper, but it is where careless marks go — a rounding instruction ignored, a percentage taken of the wrong amount, a bound taken from the wrong end of an interval. This free revision engine covers the number content of GCSE and International GCSE Maths, from place value and the four operations through to surds, bounds and reverse percentages. It generates a new question every time and marks your answer as you go, at Foundation or Higher tier.
What the number revision engine covers
Foundation and Higher Ordering and place value — putting integers, decimals, fractions and percentages in order The four operations — including multi-step money and measurement problems Order of operations — brackets, indices, then multiplication and division Primes, factors and multiples — prime factorisation, HCF and LCM Systematic listing — counting outcomes without missing any Powers and roots — squares, cubes and their roots Indices — the index laws for multiplication, division and powers of powers Fractions and exact calculation — adding, subtracting, multiplying and dividing Standard form — writing and calculating with numbers in the form a × 10ⁿ Percentages — of an amount, increase and decrease, and percentage change Compound interest and decay — repeated percentage change over several years Fraction, decimal and percentage equivalence — converting between all three Rounding and estimation — to decimal places, significant figures and by rounding to 1 s.f. Error intervals — the range a rounded measurement could have come from Standard units and measures — converting length, area, volume, mass and time Higher tier as well Fractional and negative indices — including evaluating them exactly Surds — simplifying, adding and rationalising a denominator The product rule for counting — the number of arrangements over several stages Upper and lower bounds — including bounds in a calculation Compound growth and decay — repeated change, and how many years to reach a target Primes and proof — using prime factorisation to justify a result Significant figures and truncation — and the difference between them Reverse percentages — working back to the original amount
Number formulas and results you need to know
Percentage change. New value = original × multiplier. A 15% increase is × 1.15; a 15% decrease is × 0.85. Reverse percentages. If a price after a 20% reduction is £48, divide by 0.8 to get the original, not add 20%. Compound interest. Final value = P × (1 + r/100)ⁿ, where n is the number of years. Simple interest adds the same amount each year; compound interest does not. Bounds. A length given as 12 cm to the nearest centimetre lies between 11.5 cm and 12.5 cm. For a quotient, the upper bound uses the largest numerator and the smallest denominator. Standard form. a × 10ⁿ where a is greater than (or equal to) 1 but less than 10. When multiplying, multiply the numbers and add the powers, then adjust so a is back between 1 and 10. HCF and LCM. For any two numbers, HCF × LCM = the product of the numbers. Index laws. xᵃ × xᵇ = xᵃ⁺ᵇ, xᵃ ÷ xᵇ = xᵃ⁻ᵇ, (xᵃ)ᵇ = xᵃᵇ, x⁰ = 1, and x⁻ⁿ = 1/xⁿ. Area and volume units. 1 m² = 10 000 cm², and 1 m³ = 1 000 000 cm³. Convert the units, not just the number.
How to use it
Choose Foundation or Higher, then pick a topic. The engine generates a question, you type your answer, and it marks it straight away — accepting any equivalent form, so a fraction, a decimal or a percentage all count where they are genuinely equal. Questions range from single-step recall to multi-step problems that carry a value from one stage into the next. Signing in saves your accuracy per topic to your GCSE skill tree.
More GCSE Maths revision
Number underpins almost everything else: percentages feed into ratio and proportion, bounds into measurement, and indices into algebra. Every topic and your progress across all of them is on the revision hub. All of our revision engines are free to use.