Number — OCR GCSE MathsTopics in Number for OCR GCSE Maths. Choose a topic for explanations and practice.Integers, Powers & RootsFactors, Multiples & PrimesFractions, Decimals & PercentagesPercentages: Increase & DecreasePercentage Change & Reverse PercentagesRatio of AmountsIndices & Standard FormSurdsRounding & EstimationBounds & Error IntervalsRecurring DecimalsStart practice Back to OCR GCSE Maths