Mathitat
Serious maths,gently done.
Number
Common factorCommon multipleComposite numberCube numberCube rootDecimalDecimal placeDenominatorDifferenceDigitDivisibilityEquivalent fractionError intervalEven numberExponentFactorFactor pairFractionHighest common factor (HCF)Improper fractionIndexIntegerInverse operationIrrational numberLower boundLowest common multiple (LCM)Mixed numberMultipleNegative numberNumeratorOdd numberOperationOrder of operationsPercentagePlace valuePowerPrimePrime factorPrime factorisationProductQuotientRational numberRationaliseReciprocalRecurring decimalRemainderSignificant figureSquare numberSquare rootStandard formSumSurdTerminating decimalUpper bound
Algebra
Arithmetic sequenceAxisCoefficientCommon differenceComplete the squareComposite functionConstantCoordinateDifference of two squaresEquationEquation of a lineExpressionFormulaFunctionGeometric sequenceGradientIdentityInequalityInterceptInverse functionLike termsMidpointnth termOriginParabolaQuadraticQuadratic formulaRootSequenceSimultaneous equationsSolutionSubject of a formulaTermTurning pointVariable
Ratio & proportion
Geometry & measures
Acute angleAlternate anglesAngleArcAreaBearingBisectorCapacityChordCircumferenceCo-interior anglesConeCongruentCorresponding anglesCosineCross-sectionCuboidCylinderDegreeDiagonalDiameterEnlargementEquilateral triangleExterior angleHypotenuseInterior angleIsosceles triangleLine of symmetryLocusMagnitudeMassObtuse angleParallelPerimeterPerpendicularPolygonPrismPyramidPythagoras' theoremQuadrilateralRadiusReflectionReflex angleRegular polygonRight angleRotationRotational symmetryScale factorScalene triangleSectorSegmentSimilarSineSphereSurface areaSymmetryTangentTransformationTranslationTrigonometryVectorVertexVertically opposite anglesVolume
Probability
Statistics
AverageBar chartClass intervalContinuous dataCorrelationCumulative frequencyDataDiscrete dataFrequencyFrequency densityFrequency polygonHistogramInterquartile rangeLine of best fitMeanMedianModal classModeOutlierPictogramPie chartPopulationPrimary dataQualitative dataQuantitative dataQuartileRangeSampleScatter graphSecondary dataStem-and-leaf diagramTallyTwo-way table
Command words
Prove
Practise thisGive a full proof — every step shown, with reasons.
In Español · sample
demostrarDa una demostración completa: cada paso mostrado, con razones.Q Prove that the sum of two even numbers is always even.
A
Let the numbers be 2a and 2b (any even numbers).
2a + 2b = 2(a + b) — a multiple of 2, so the sum is always even. ∎
A proof must work for ALL cases — examples alone are not a proof.