KS2 maths glossary

The maths words children meet in Key Stage 2 and the 11+, each explained simply with a worked example, the common mistake and a practice question.

Number

Prime number
A prime number is a whole number with exactly two factors: 1 and itself.
Factor
A factor is a whole number that divides into another number exactly, with nothing left over.
Multiple
A multiple of a number is what you get when you multiply it by a whole number: the answers in its times table.
Square number
A square number is what you get when you multiply a whole number by itself.
Cube number
A cube number is what you get when you multiply a whole number by itself, and then by itself again.
Integer
An integer is a whole number, positive, negative or zero, with no fraction or decimal part.
Negative numbers
Negative numbers are numbers less than zero, written with a minus sign, like −5.
Place value
Place value is the value a digit has because of where it sits in a number.
BODMAS
BODMAS is the order to do a calculation in: Brackets, then Orders, then Division and Multiplication, then Addition and Subtraction.

Fractions, decimals and percentages

Fraction
A fraction is a way of writing part of a whole, with one number over another, like ¾.
Numerator
The numerator is the top number of a fraction, and it tells you how many of the equal parts you have.
Denominator
The denominator is the bottom number of a fraction, and it tells you how many equal parts the whole is split into.
Improper fraction
An improper fraction has a numerator that is bigger than, or equal to, its denominator, like 7/4.
Mixed number
A mixed number is a whole number and a fraction written together, like 2½.
Decimal
A decimal is a number with a decimal point, where the digits after the point show parts of a whole.
Percentage
A percentage is a number out of 100, so 35% means 35 out of every 100.

Ratio, proportion and algebra

Averages and data

Perimeter, area and volume

Angles, lines and position

Types of angles
Angles are named by their size: acute is less than 90°, right is exactly 90°, obtuse is between 90° and 180°, and reflex is between 180° and 360°.
Parallel lines
Parallel lines are lines that stay the same distance apart and never meet, however far they go.
Perpendicular lines
Perpendicular lines meet or cross at a right angle, which is 90°.
Line of symmetry
A line of symmetry splits a shape into two halves that are mirror images of each other.
Coordinates
Coordinates are a pair of numbers that give the exact position of a point on a grid, like (3, 5).

More ways to practise

For shapes, see 2D and 3D shapes and their properties. For factors of any number up to 100, see factors of numbers from 2 to 100. The 11+ maths topics guide shows how these words turn up in real questions.

Questions parents ask

Which maths words does my child need to know for the 11+?

The vocabulary of the Key Stage 2 curriculum: words like factor, multiple, prime, numerator, ratio, mean, perimeter and perpendicular. 11+ questions use them without explaining them, so a child who half knows a word can lose an easy mark.

Are the median, mode and range in the primary curriculum?

No. Year 6 teaches the mean. The median, mode and range are taught in Key Stage 3, but some 11+ papers include them, so they are in this glossary too.

How can I help my child learn maths vocabulary?

Use the words in everyday talk: "is 24 a multiple of 6?" at the shops, "what fraction is left?" at tea. Ask your child to explain a word back in their own words, which shows quickly whether they really know it.

Knowing the words is half of an 11+ maths question

11+ papers use maths vocabulary without explaining it. The free diagnostic checks maths, English and both kinds of reasoning, and shows what to practise next. No card is required.

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