Key Stage 3‎ > ‎

### KS3 Mathematics

The National Curriculum for Mathematics in Key Stage 3. Hover over blue text to see non-statutory examples.

## Working mathematically

Through the mathematics content, pupils should be taught to:

### Develop fluency

• consolidate their numerical and mathematical capability from key stage 2 and extend their understanding of the number system and place value to include decimals, fractions, powers and roots
• select and use appropriate calculation strategies to solve increasingly complex problems
• use algebra to generalise the structure of arithmetic, including to formulate mathematical relationships
• substitute values in expressions, rearrange and simplify expressions, and solve equations
• move freely between different numerical, algebraic, graphical and diagrammatic representations
• develop algebraic and graphical fluency, including understanding linear and simple quadratic functions
• use language and properties precisely to analyse numbers, algebraic expressions, 2-D and 3-D shapes, probability and statistics

### Reason mathematically

• extend their understanding of the number system; make connections between number relationships, and their algebraic and graphical representations
• extend and formalise their knowledge of ratio and proportion in working with measures and geometry, and in formulating proportional relations algebraically
• identify variables and express relations between variables algebraically and graphically
• make and test conjectures about patterns and relationships; look for proofs or counter-examples
• begin to reason deductively in geometry, number and algebra, including using geometrical constructions
• interpret when the structure of a numerical problem requires additive, multiplicative or proportional reasoning
• explore what can and cannot be inferred in statistical and probabilistic settings, and begin to express their arguments formally

### Solve problems

• develop their mathematical knowledge, in part through solving problems and evaluating the outcomes, including multi-step problems
• develop their use of formal mathematical knowledge to interpret and solve problems, including in financial mathematics
• begin to model situations mathematically and express the results using a range of formal mathematical representations
• select appropriate concepts, methods and techniques to apply to unfamiliar and non-routine problems

## Number

Pupils should be taught to:
• understand and use place value for decimals, measures and integers of any size
• order positive and negative integers, decimals and fractions; use the number line as a model for ordering of the real numbers; use the symbols =, ≠, <, >, ≤, ≥
• use the concepts and vocabulary of prime numbers, factors (or divisors), multiples, common factors, common multiples, highest common factor, lowest common multiple, prime factorisation, including using product notation and the unique factorisation property
• use the 4 operations, including formal written methods, applied to integers, decimals, proper and improper fractions, and mixed numbers, all both positive and negative
• use conventional notation for the priority of operations, including brackets, powers, roots and reciprocals
• recognise and use relationships between operations including inverse operations
• use integer powers and associated real roots (square, cube and higher), recognise powers of 2, 3, 4, 5 and distinguish between exact representations of roots and their decimal approximations
• interpret and compare numbers in standard form A x 10n 1≤A<10, where n is a positive or negative integer or 0
• work interchangeably with terminating decimals and their corresponding fractions (such as 3.5 and or 0.375 and )
• define percentage as ‘number of parts per hundred’, interpret percentages and percentage changes as a fraction or a decimal, interpret these multiplicatively, express 1 quantity as a percentage of another, compare 2 quantities using percentages, and work with percentages greater than 100%
• interpret fractions and percentages as operators
• use standard units of mass, length, time, money and other measures, including with decimal quantities
• round numbers and measures to an appropriate degree of accuracy
• use approximation through rounding to estimate answers and calculate possible resulting errors expressed using inequality notation a<x≤b
• use a calculator and other technologies to calculate results accurately and then interpret them appropriately
• appreciate the infinite nature of the sets of integers, real and rational numbers

## Algebra

Pupils should be taught to:
• use and interpret algebraic notation, including:
• ab in place of a × b
• 3y in place of y + y + y and 3 × y
• a² in place of a × a, a³ in place of a × a × a; a²b in place of a × a × b
• in place of a ÷ b
• coefficients written as fractions rather than as decimals
• brackets
• substitute numerical values into formulae and expressions, including scientific formulae
• understand and use the concepts and vocabulary of expressions, equations, inequalities, terms and factors
• simplify and manipulate algebraic expressions to maintain equivalence by:
• collecting like terms
• multiplying a single term over a bracket
• taking out common factors
• expanding products of 2 or more binomials
• understand and use standard mathematical formulae; rearrange formulae to change the subject
• model situations or procedures by translating them into algebraic expressions or formulae and by using graphs
• use algebraic methods to solve linear equations in 1 variable (including all forms that require rearrangement)
• work with coordinates in all 4 quadrants
• recognise, sketch and produce graphs of linear and quadratic functions of 1 variable with appropriate scaling, using equations in x and y and the Cartesian plane
• interpret mathematical relationships both algebraically and graphically
• reduce a given linear equation in two variables to the standard form y = mx + c; calculate and interpret gradients and intercepts of graphs of such linear equations numerically, graphically and algebraically
• use linear and quadratic graphs to estimate values of y for given values of x and vice versa and to find approximate solutions of simultaneous linear equations
• find approximate solutions to contextual problems from given graphs of a variety of functions, including piece-wise linear, exponential and reciprocal graphs
• generate terms of a sequence from either a term-to-term or a position-to-term rule
• recognise arithmetic sequences and find the nth term
• recognise geometric sequences and appreciate other sequences that arise

## Ratio, proportion and rates of change

Pupils should be taught to:
• change freely between related standard units
• use scale factors, scale diagrams and maps
• express 1 quantity as a fraction of another, where the fraction is less than 1 and greater than 1
• use ratio notation, including reduction to simplest form
• divide a given quantity into 2 parts in a given part:part or part:whole ratio; express the division of a quantity into 2 parts as a ratio
• understand that a multiplicative relationship between 2 quantities can be expressed as a ratio or a fraction
• relate the language of ratios and the associated calculations to the arithmetic of fractions and to linear functions
• solve problems involving percentage change, including: percentage increase, decrease and original value problems and simple interest in financial mathematics
• solve problems involving direct and inverse proportion, including graphical and algebraic representations
• use compound units such as speed, unit pricing and density to solve problems

## Geometry and measures

Pupils should be taught to:
• derive and apply formulae to calculate and solve problems involving: perimeter and area of triangles, parallelograms, trapezia, volume of cuboids (including cubes) and other prisms (including cylinders)
• calculate and solve problems involving: perimeters of 2-D shapes (including circles), areas of circles and composite shapes
• draw and measure line segments and angles in geometric figures, including interpreting scale drawings
• derive and use the standard ruler and compass constructions (perpendicular bisector of a line segment, constructing a perpendicular to a given line from/at a given point, bisecting a given angle); recognise and use the perpendicular distance from a point to a line as the shortest distance to the line
• describe, sketch and draw using conventional terms and notations: points, lines, parallel lines, perpendicular lines, right angles, regular polygons, and other polygons that are reflectively and rotationally symmetric
• use the standard conventions for labelling the sides and angles of triangle ABC, and know and use the criteria for congruence of triangles
• derive and illustrate properties of triangles, quadrilaterals, circles, and other plane figures using appropriate language and technologies
• identify properties of, and describe the results of, translations, rotations and reflections applied to given figures
• identify and construct congruent triangles, and construct similar shapes by enlargement, with and without coordinate grids
• apply the properties of angles at a point, angles at a point on a straight line, vertically opposite angles
• understand and use the relationship between parallel lines and alternate and corresponding angles
• derive and use the sum of angles in a triangle and use it to deduce the angle sum in any polygon, and to derive properties of regular polygons
• apply angle facts, triangle congruence, similarity and properties of quadrilaterals to derive results about angles and sides, including Pythagoras’ Theorem, and use known results to obtain simple proofs
• use Pythagoras’ Theorem and trigonometric ratios in similar triangles to solve problems involving right-angled triangles
• use the properties of faces, surfaces, edges and vertices of cubes, cuboids, prisms, cylinders, pyramids, cones and spheres to solve problems in 3-D
• interpret mathematical relationships both algebraically and geometrically

## Probability

Pupils should be taught to:
• record, describe and analyse the frequency of outcomes of simple probability experiments involving randomness, fairness, equally and unequally likely outcomes, using appropriate language and the 0-1 probability scale
• understand that the probabilities of all possible outcomes sum to 1
• enumerate sets and unions/intersections of sets systematically, using tables, grids and Venn diagrams
• generate theoretical sample spaces for single and combined events with equally likely, mutually exclusive outcomes and use these to calculate theoretical probabilities

## Statistics

Pupils should be taught to:
• describe, interpret and compare observed distributions of a single variable through: appropriate graphical representation involving discrete, continuous and grouped data; and appropriate measures of central tendency (mean, mode, median) and spread (range, consideration of outliers)
• construct and interpret appropriate tables, charts, and diagrams, including frequency tables, bar charts, pie charts, and pictograms for categorical data, and vertical line (or bar) charts for ungrouped and grouped numerical data
• describe simple mathematical relationships between 2 variables (bivariate data) in observational and experimental contexts and illustrate using scatter graphs