IGCSE›Edexcel IGCSE Maths›Mind mapsNumber ToolkitEdexcel IGCSE Maths: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsIntegersIntegers are whole numbers: negative, zero or positivePlace value: in 420742074207, the 2 is worth 200Negatives get smaller as magnitude grows: −8<−3<0-8 < -3 < 0−8<−3<0−40-40−40 is smaller than −4-4−4Negative numbersAdding a negative = subtracting: 5+(−3)=25 + (-3) = 25+(−3)=2Subtracting a negative = adding: 5−(−3)=85 - (-3) = 85−(−3)=8Same signs multiply or divide to give a positiveDifferent signs give a negative: (−4)×2=−8(-4) \times 2 = -8(−4)×2=−8Factors & primesA factor divides exactly with no remainderA prime has exactly two factors: 1 and itself1 is not prime; 2 is the only even primePrime factorisation: 60=22×3×560 = 2^2 \times 3 \times 560=22×3×5HCF uses shared primes; LCM uses highest powersNumber Toolkitintegers to BIDMASn2n^2n2n3n^3n3HCFLCMSquares & cubesSquare numbers: 1,4,9,16,25,36,49,641, 4, 9, 16, 25, 36, 49, 641,4,9,16,25,36,49,64Cube numbers: 1,8,27,64,1251, 8, 27, 64, 1251,8,27,64,125Roots reverse powers: 49=7\sqrt{49} = 749=7, 273=3\sqrt[3]{27} = 3327=3Every positive number has two square roots: ±5\pm 5±5BIDMASBrackets, Indices, DM, AS in that orderDivision and multiplication share priority: go left to rightAddition and subtraction share priority: go left to right3+4×22=3+16=193 + 4 \times 2^2 = 3 + 16 = 193+4×22=3+16=19Exam tipsRewrite double signs first: −−- -−− becomes +Squaring is n×nn \times nn×n, not 2×n2 \times n2×n2+3×4=142 + 3 \times 4 = 142+3×4=14, not 20Use prime factorisation to find HCF and LCM