IGCSE›Edexcel IGCSE Maths›Mind mapsStandard & Compound UnitsEdexcel IGCSE Maths: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsMetric units1 km=1000 m1\,\text{km} = 1000\,\text{m}1km=1000m, 1 m=100 cm1\,\text{m} = 100\,\text{cm}1m=100cm1 tonne=1000 kg1\,\text{tonne} = 1000\,\text{kg}1tonne=1000kg1 litre=1000 cm31\,\text{litre} = 1000\,\text{cm}^31litre=1000cm3Big to small: multiply; small to big: divideArea and volumeArea conversion: square the factorVolume conversion: cube the factor1 m2=10 000 cm21\,\text{m}^2 = 10\,000\,\text{cm}^21m2=10000cm21 m3=1 000 000 cm31\,\text{m}^3 = 1\,000\,000\,\text{cm}^31m3=1000000cm3Unitsstandard and compoundkmmcmkggDensitydensity=massvolume\text{density} = \frac{\text{mass}}{\text{volume}}density=volumemassUnits g/cm³ or kg/m³45 g÷15 cm3=3 g/cm345\,\text{g} \div 15\,\text{cm}^3 = 3\,\text{g/cm}^345g÷15cm3=3g/cm3Check mass and volume units matchSpeed and pressurespeed=distancetime\text{speed} = \frac{\text{distance}}{\text{time}}speed=timedistancepressure=forcearea\text{pressure} = \frac{\text{force}}{\text{area}}pressure=areaforcekm/h to m/s: multiply by 518\frac{5}{18}185m/s to km/h: multiply by 185\frac{18}{5}51872 km/h=72\,\text{km/h} = 72km/h= 20 m/sExam tipsDo not just multiply by 100 for m² to cm²Use a formula triangle to rearrangeAlways give units in the answer