Maths Words

An angle less than 90°.

Example: 35° is acute.

Don't mix up with: Obtuse angle

Learn it on: Angles (S1)

In trigonometry, the side next to the marked angle that isn't the hypotenuse.

Don't mix up with: Opposite

Learn it on: Right-Angled Trigonometry (S3)

Tiles that stand for x and for 1, used to show collecting like terms and adding negatives.

Learn it on: Expressions and Substitution (S1), Integers (S1)

Equal angles on opposite sides of a line that crosses two parallel lines (a Z shape).

Don't mix up with: Corresponding angles

Learn it on: Angles (S1)

The amount of turn between two lines that meet, measured in degrees (°).

Example: A full turn is 360°.

When something goes up in value over time.

Example: A house that appreciates by 4% a year.

Don't mix up with: Depreciation

Learn it on: Percentages (S3)

Part of the circumference of a circle.

Example: Arc length = (angle ÷ 360) × πd

Don't mix up with: Chord

Learn it on: Arcs and Sectors (S3)

The amount of flat space inside a shape, measured in square units.

Example: A 5 cm by 3 cm rectangle has area 5 × 3 = 15 cm².

Don't mix up with: Perimeter

Learn it on: Area & Perimeter (S1), Circles (S2)

A single value that represents a set of data: the mean, median or mode.

Learn it on: Statistics (S2)

One of the two number lines on a grid. The x-axis goes across and the y-axis goes up. The plural is axes.

Learn it on: Coordinates (S1), Straight Line (S2)

Our way of solving equations: do the same to both sides to keep them equal, and write what you did beside each line.

Example: 2x + 3 = 11 → 2x = 8 (− 3 both sides) → x = 4 (÷ 2 both sides)

Learn it on: Equations (S1)

A graph that uses bars of different heights to compare amounts.

Don't mix up with: Line graph

Learn it on: Graphs (S2)

A diagram that shows an amount as a bar split into equal boxes.

Example: ¾ of 28: split 28 into 4 boxes of 7, then take 3 boxes.

Learn it on: Fractions (S1)

The option that gives you the most for your money. Work out the cost of one item (or one gram) for each option, then compare.

Example: Pack A: 0.48p per gram. Pack B: 0.45p per gram. Pack B is the best buy, since 0.45 < 0.48.

Learn it on: Money (S2)

The order to work out a calculation: Brackets, Orders (powers), Divide and Multiply, then Add and Subtract.

Example: 3 + 4 × 5 = 3 + 20 = 23

Learn it on: Order of Operations (S1), Integers (S1)

Our name for short division. The number you are dividing goes inside, the number you divide by goes outside, and the answer goes on top.

Example: 936 ÷ 4 = 234

Learn it on: Dividing (S1), Decimals (S1), Decimals (S2)

Work out an answer, showing your working. You can usually use a calculator.

Example: Calculate the area of the circle.

How much a container can hold, often in litres or millilitres. 1 litre = 1000 cm³.

Example: A jug with a capacity of 1.5 litres.

Don't mix up with: Volume

Learn it on: Measurement (S2), Volume (S2)

In a chimney sum, when a column makes 10 or more, the ten moves into the next column. We write it small, above the next digit of the top number.

Example: 476 + 358: 6 + 8 = 14, so write 4 and carry 1 into the tens.

Don't mix up with: Exchange

Learn it on: Adding and Subtracting (S1), Multiplying (S1)

Our name for a calculation written in columns (adding, subtracting or multiplying), with the bigger number on top and the units lined up.

Example: 476 on top, + 358 underneath, then add each column from the right.

Learn it on: Adding and Subtracting (S1), Multiplying (S1)

A straight line joining two points on a circle.

Example: A diameter is the longest chord.

Don't mix up with: Arc

Learn it on: Pythagoras in a Circle (S3), Angles in Circles (S3)

The distance all the way round a circle: its perimeter. C = πd.

Example: Diameter 10 cm: C = 3.14 × 10 = 31.4 cm.

Don't mix up with: Area

Learn it on: Circles (S2)

The number in front of a letter.

Example: In 5x, the coefficient is 5.

Learn it on: Brackets and Factorising (S2), Expanding Brackets (S3)

Extra pay worked out as a percentage of what you sell.

Example: 2% commission on £45 000 of sales = £900.

Learn it on: Wages and Salaries (S3)

A denominator that two fractions share, so they can be added or taken away.

Example: ⅔ + ¼: change both to twelfths, 8/12 + 3/12.

Learn it on: Fractions 2 (S1)

Say what the numbers show about the two groups, and quote the numbers.

Example: On average Class A scored higher, since 68 > 62.

Two angles that add up to 90°.

Example: 30° and 60° are complementary.

Don't mix up with: Supplementary angles

Learn it on: Angles (S1)

Interest added each year on to the amount in the account, so the next year's interest is worked out on a bigger amount.

Example: £1000 at 3% for 2 years: 1000 × 1.03² = £1060.90

Don't mix up with: Appreciation

Learn it on: Percentages (S3)

The theorem the other way round: if c² = a² + b², the triangle must be right-angled.

Don't mix up with: Pythagoras' theorem

Learn it on: Converse of Pythagoras (S3)

Change a measurement into a different unit. Bigger unit to smaller unit: ×. Smaller unit to bigger unit: ÷.

Example: 3.5 m = 3.5 × 100 = 350 cm

Learn it on: Measurement (S2), Scale (S2)

A pair of numbers (x, y) that gives the position of a point: along first, then up or down.

Example: (3, 2) is 3 along and 2 up.

Learn it on: Coordinates (S1), Straight Line (S2)

Equal angles in matching positions where a line crosses two parallel lines (an F shape).

Don't mix up with: Alternate angles

Learn it on: Angles (S1)

The shape you see if you slice straight through a prism.

Example: The cross-section of a cylinder is a circle.

Learn it on: Volume (S2)

The answer when a whole number is multiplied by itself three times.

Example: 2³ = 2 × 2 × 2 = 8

Don't mix up with: Cube root

Learn it on: Powers and Roots (S2)

The number that was multiplied by itself three times to make a cube number.

Example: ∛27 = 3, because 3 × 3 × 3 = 27.

Don't mix up with: Cube number

Learn it on: Powers and Roots (S2)

The type of money used in a country.

Example: The euro (€) and the US dollar ($) are currencies.

Learn it on: Money (S2)

A prism with a circle as its cross-section. Volume = πr²h.

Example: A tin of beans is a cylinder.

Learn it on: Volume (S2), Volume (S3)

A number with a decimal point, showing parts of a whole in tenths, hundredths and so on.

Example: 0.75 is 7 tenths and 5 hundredths.

Learn it on: Decimals (S1), Fractions, Decimals and Percentages (S1)

A position after the decimal point: tenths, hundredths, thousandths and so on.

Example: 3.47 has 2 decimal places.

Don't mix up with: Significant figures

Learn it on: Decimals (S1), Decimals (S2)

A time written as a decimal number of hours. Multiply the decimal part by 60 to get minutes.

Example: 2.5 hours = 2 hours 30 minutes. 0.25 h = 15 min.

Learn it on: Speed, Distance and Time (S2)

Money taken off your pay, such as income tax, National Insurance and pension.

Example: Deductions = £215.40 + £118.60 + £98.80 = £432.80

Learn it on: Wages and Salaries (S3)

The bottom number of a fraction. It tells you how many equal parts the whole is split into.

Example: In ¾, the denominator is 4.

Don't mix up with: Numerator

Learn it on: Fractions (S1), Fractions 2 (S1)

When something goes down in value over time.

Example: A car that depreciates by 15% a year.

Don't mix up with: Appreciation

Learn it on: Percentages (S3)

Work out the answer, showing how you got it.

Example: Determine whether the triangle is right-angled.

The distance right across a circle, through the centre. It is twice the radius.

Example: A circle with radius 4 cm has diameter 8 cm.

Don't mix up with: Radius

Learn it on: Circles (S2), Angles in Circles (S3)

How far apart two numbers are: the bigger one take away the smaller one.

Example: The difference between 12 and 7 is 5.

Learn it on: Adding and Subtracting (S1)

One of the ten symbols 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 used to write numbers.

Example: 472 has three digits: 4, 7 and 2.

A statement with an equals sign, where the two sides are worth the same. You can solve it to find the letter.

Example: 2x + 3 = 11

Don't mix up with: Expression, Formula

Learn it on: Equations (S1), Equations and Inequations (S3)

A triangle with all three sides equal and all three angles 60°.

Learn it on: Angles (S1)

Fractions that are worth the same, even though they look different.

Example: ½ = 2/4 = 5/10

Learn it on: Fractions (S1)

A rough answer, worked out with rounded numbers, to check that the real answer is sensible.

Example: 3.47 × 6 is about 3.5 × 6 = 21.

Learn it on: Multiplying (S1), Decimals (S1)

Work out the value of something, often without a calculator.

Example: Evaluate 3² + 4 × 5.

Don't round. Leave the answer as a fraction, or in terms of π or a square root.

Example: Give the exact value: 1/3, not 0.333.

In a subtraction, when the top digit is too small, take 1 from the next column. It becomes 10 in the column you need.

Example: 742 − 385: 2 − 5 won't go, so exchange 1 ten: 4 tens become 3, and 2 becomes 12.

Don't mix up with: Carry

Learn it on: Adding and Subtracting (S1)

How much one currency is worth in another currency.

Example: £1 = $1.27

Don't mix up with: Exchange

Learn it on: Money (S2)

Multiply out a bracket: multiply every term inside by the term outside.

Example: 3(x + 4) = 3x + 12

Don't mix up with: Factorise

Learn it on: Expressions and Substitution (S1), Brackets and Factorising (S2), Expanding Brackets (S3)

Give a reason, in words, using the numbers from the question.

Example: Explain why the triangle is not right-angled.

Write something in a particular form.

Example: Express 0.000 34 in standard form.

A collection of terms with no equals sign.

Example: 3x + 2

Don't mix up with: Equation

Learn it on: Expressions and Substitution (S1), Brackets and Factorising (S2)

A number that divides exactly into another number, with nothing left over.

Example: The factors of 12 are 1, 2, 3, 4, 6 and 12.

Don't mix up with: Multiple

Learn it on: Types of Numbers (S1), Brackets and Factorising (S2)

A diagram that splits a number into factor pairs until every branch ends in a prime number.

Example: 60 → 6 × 10 → 2 × 3 × 2 × 5

Learn it on: Types of Numbers (S1)

The opposite of expanding: take out the highest common factor and write it outside a bracket.

Example: 12a − 18 = 6(2a − 3)

Don't mix up with: Expand

Learn it on: Brackets and Factorising (S2)

Work out the answer. It may need working, so show it.

Example: Find the size of angle x.

A rule, written with letters, that shows how to work something out. The plural is formulae.

Example: A = l × b

Don't mix up with: Equation

Learn it on: Expressions and Substitution (S1), Substitution (S2), Formulae (S3)

How many times something happens.

Learn it on: Graphs (S2)

How steep a line or slope is: vertical height ÷ horizontal distance.

Example: Rises 2 m over 10 m: gradient = 2/10 = 1/5.

Learn it on: Gradient (S3), Straight Line (S2)

A way to multiply by splitting both numbers into hundreds, tens and units, multiplying each pair in a grid, and adding everything in the grid.

Example: 47 × 36: 1200 + 210 + 240 + 42 = 1692.

Learn it on: Multiplying (S1)

The total amount you earn before anything is taken off.

Example: Basic pay £1400 + commission £900 = gross pay £2300.

Don't mix up with: Net pay

Learn it on: Wages and Salaries (S3)

Use the answer to the part before to help with this part.

Example: (a) Factorise x² + 5x. (b) Hence solve x² + 5x = 0.

The biggest number that is a factor of two (or more) numbers. Often shortened to HCF.

Example: The HCF of 12 and 18 is 6.

Don't mix up with: Lowest common multiple

Learn it on: Types of Numbers (S1), Brackets and Factorising (S2)

A flat line across a grid, with equation y = a number.

Example: y = 3

Don't mix up with: Vertical line

Learn it on: Straight Line (S2)

The longest side of a right-angled triangle. It is opposite the right angle.

Learn it on: Pythagoras (S3), Right-Angled Trigonometry (S3), Converse of Pythagoras (S3)

A fraction where the top number is bigger than the bottom number.

Example: 7/4 is an improper fraction.

Don't mix up with: Mixed number

Learn it on: Fractions (S1), Fractions (S2)

Like an equation, but with <, >, ≤ or ≥ instead of =. The answer is a range of values.

Example: x + 3 > 7 gives x > 4.

Learn it on: Inequations (S2), Equations and Inequations (S3)

A whole number. It can be positive, negative or zero.

Example: −3, 0 and 12 are integers. 2.5 is not.

Learn it on: Integers (S1)

The upper quartile take away the lower quartile (Q₃ − Q₁). It shows how spread out the middle half of the data is.

Example: Q₃ = 44 and Q₁ = 33.5, so IQR = 10.5

Don't mix up with: Range

Learn it on: Median, Quartiles & IQR (S3)

A triangle with two equal sides and two equal angles.

Example: Two radii and a chord make an isosceles triangle in a circle.

Learn it on: Angles (S1), Angles in Circles (S3)

Back up your answer with working or a reason. An answer on its own gets no marks.

Example: Which is the better buy? Justify your answer.

Terms with exactly the same letters, which can be collected together.

Example: 3a + 2b + a + 4b = 4a + 6b

Learn it on: Expressions and Substitution (S1), Brackets and Factorising (S2), Expanding Brackets (S3)

The smallest and largest values allowed by a tolerance.

Example: For 45 ± 1.5 g, the lower limit is 43.5 g and the upper limit is 46.5 g.

Learn it on: Tolerance (S2)

A graph with points joined by lines, often used to show how something changes over time.

Don't mix up with: Bar graph

Learn it on: Graphs (S2)

A line that splits a shape into two halves that are mirror images of each other.

Example: A square has 4 lines of symmetry.

Learn it on: Reflection Symmetry (S2)

The smallest number that is a multiple of two (or more) numbers. Often shortened to LCM.

Example: The LCM of 4 and 6 is 12.

Don't mix up with: Highest common factor

Learn it on: Types of Numbers (S1), Fractions 2 (S1)

The total of all the values divided by how many values there are.

Example: Mean of 12, 15, 9, 14 = 50 ÷ 4 = 12.5

Don't mix up with: Median, Mode

Learn it on: Statistics (S2), Standard Deviation (S3)

The middle value when the values are put in order.

Example: 3, 5, 8, 9, 12: the median is 8.

Don't mix up with: Mean, Mode

Learn it on: Statistics (S2), Median, Quartiles & IQR (S3)

A whole number and a fraction together.

Example: 1¾ is a mixed number. It is the same as 7/4.

Don't mix up with: Improper fraction

Learn it on: Fractions (S1), Fractions (S2), Fractions 2 (S1)

The value that appears most often.

Example: In 2, 3, 3, 5, 7, the mode is 3.

Don't mix up with: Mean, Median

Learn it on: Statistics (S2)

A number in the times table of another number.

Example: Multiples of 6: 6, 12, 18, 24, …

Don't mix up with: Factor

Learn it on: Types of Numbers (S1)

Round your final answer as asked: to the nearest whole number, penny, degree and so on. Only round at the end.

Example: Give your answer to the nearest cm².

A number less than zero, written with a minus sign.

Example: −5 °C is colder than −2 °C.

Learn it on: Integers (S1)

What you actually take home: gross pay take away the deductions.

Example: £2400 − £529 = £1871 net pay.

Don't mix up with: Gross pay

Learn it on: Wages and Salaries (S3)

A formula that gives any term in a sequence from its position n.

Example: The nth term 3n + 2 gives 5, 8, 11, …

Learn it on: Patterns and Sequences (S2)

The top number of a fraction.

Example: In ¾, the numerator is 3.

Don't mix up with: Denominator

Learn it on: Fractions (S1)

An angle bigger than 90° but less than 180°.

Example: 130° is obtuse.

Don't mix up with: Acute angle, Reflex angle

Learn it on: Angles (S1)

In trigonometry, the side across from the marked angle.

Don't mix up with: Adjacent

Learn it on: Right-Angled Trigonometry (S3)

The point (0, 0), where the axes cross.

Learn it on: Coordinates (S1)

Hours worked on top of normal hours, usually paid at a higher rate.

Example: Time and a half: £12 an hour becomes £18 an hour.

Learn it on: Wages and Salaries (S3)

Lines that go in the same direction and never meet, marked with arrows.

Example: Railway tracks are parallel.

Don't mix up with: Perpendicular

Learn it on: Angles (S1)

A number out of 100. Per cent means "out of 100".

Example: 37% = 37/100 = 0.37

Learn it on: Percentages (S1), Fractions, Decimals and Percentages (S1), Percentages (S2), Percentages (S3)

How much something has gone up or down, as a percentage of the original amount: change ÷ original × 100.

Example: £50 to £60: 10 ÷ 50 × 100 = 20% increase.

Learn it on: Percentages (S2)

Making an amount smaller by a percentage of itself: find the percentage, then take it away.

Example: Decrease £45 by 10%: 10% = £4.50, so £40.50.

Don't mix up with: Percentage increase

Learn it on: Percentages (S1), Percentages (S2)

Making an amount bigger by a percentage of itself: find the percentage, then add it on.

Example: Increase £60 by 20%: 20% = £12, so £72.

Don't mix up with: Percentage decrease

Learn it on: Percentages (S1), Percentages (S2)

The distance all the way round the outside of a shape.

Example: A 5 cm by 3 cm rectangle has perimeter 5 + 3 + 5 + 3 = 16 cm.

Don't mix up with: Area

Learn it on: Area & Perimeter (S1)

Lines that meet at a right angle.

Example: The edges at the corner of a table are perpendicular.

Don't mix up with: Parallel

The number you get when you divide any circle's circumference by its diameter, written π. It is about 3.14. In S2 we use 3.14; in S3 we use the π button.

Example: C = πd and A = πr²

Learn it on: Circles (S2), Arcs and Sectors (S3)

A circle split into slices to show how a total is shared out. Each slice's angle is its fraction of 360°.

Example: 1/3 of the pupils walk: 1/3 × 360° = 120°

Learn it on: Graphs (S2)

What a digit is worth because of the column it is in.

Example: In 3.472, the 4 is worth 4 tenths (0.4).

Learn it on: Decimals (S1), Multiplying (S1), Dividing (S1)

The small raised number that tells you how many times to multiply a number by itself. Also called an index.

Example: 2⁵ = 2 × 2 × 2 × 2 × 2 = 32

Learn it on: Powers and Roots (S2), Types of Numbers (S1), Standard Form (S2)

Writing a number as a product of prime numbers, often using powers.

Example: 60 = 2 × 2 × 3 × 5 = 2² × 3 × 5

Learn it on: Types of Numbers (S1)

A number with exactly two factors: 1 and itself. 1 is not prime.

Example: 2, 3, 5, 7, 11 and 13 are prime numbers.

Learn it on: Types of Numbers (S1)

A 3D shape with the same cross-section all the way through.

Example: A triangular prism, a cuboid and a cylinder.

Learn it on: Volume (S2), Volume (S3)

The answer when you multiply numbers together.

Example: The product of 4 and 5 is 20.

Don't mix up with: Sum

Learn it on: Multiplying (S1)

In a right-angled triangle, the square on the hypotenuse equals the sum of the squares on the other two sides: c² = a² + b².

Example: 3² + 4² = 9 + 16 = 25 = 5²

Don't mix up with: Converse

Learn it on: Pythagoras (S3), Pythagoras in a Circle (S3)

One of the four parts a grid is split into by the axes.

Example: (−2, 3) is in the second quadrant.

Learn it on: Coordinates (S1)

The values a quarter of the way (Q₁) and three quarters of the way (Q₃) through the ordered data. The median is Q₂.

Learn it on: Median, Quartiles & IQR (S3)

The answer when you divide one number by another.

Example: In 20 ÷ 4 = 5, the quotient is 5.

Learn it on: Dividing (S1)

The distance from the centre of a circle to its edge. It is half the diameter. The plural is radii.

Example: A circle with diameter 10 cm has radius 5 cm.

Don't mix up with: Diameter

Learn it on: Circles (S2), Arcs and Sectors (S3), Pythagoras in a Circle (S3)

The highest value take away the lowest value. It shows how spread out the values are.

Example: 2, 3, 3, 5, 7: range = 7 − 2 = 5

Learn it on: Statistics (S2)

A table with two columns showing how two amounts go together, with an arrow showing the × or ÷ step between rows.

Example: £1 = €1.16, so £200 = 1.16 × 200 = €232.

Learn it on: Money (S2), Scale (S2)

A decimal where a digit (or group of digits) repeats for ever. A dot is drawn over the repeating digit.

Example: 1 ÷ 3 = 0.333…

Learn it on: Decimals (S2)

A flip in a mirror line. Every point ends up the same distance from the line, on the other side.

Learn it on: Reflection Symmetry (S2), Rotational Symmetry and Transformations (S2)

An angle bigger than 180° but less than 360°.

Example: 250° is reflex.

Don't mix up with: Obtuse angle

Learn it on: Angles (S1)

What is left over when a number doesn't divide exactly. We usually keep dividing past the decimal point instead, and only use a remainder when the question needs one.

Example: 75 pupils in minibuses of 8: 75 ÷ 8 = 9 r 3, so 10 minibuses are needed.

Learn it on: Dividing (S1)

An angle of exactly 90°, marked with a small square.

Example: The corner of a page is a right angle.

Learn it on: Angles (S1), Pythagoras (S3)

A shape has rotational symmetry if it looks the same after a turn of less than a full turn. The order is how many times it fits onto itself in one full turn.

Example: A square has rotational symmetry of order 4.

Learn it on: Rotational Symmetry and Transformations (S2)

Write a number to a simpler value close to it. Look at the next digit: 5 or more rounds up.

Example: 7.2846 rounded to 2 decimal places is 7.28.

Learn it on: Decimals (S1), Significant Figures (S2)

Pay given as a fixed amount for a whole year.

Example: An annual salary of £31 200 is £31 200 ÷ 12 = £2600 a month.

Don't mix up with: Wage

Learn it on: Wages and Salaries (S3)

How a length on a map or drawing compares with the real length.

Example: 1 cm : 3 m means 1 cm on the plan is 3 m in real life.

Learn it on: Scale (S2)

The number you multiply by to enlarge or reduce a shape: new length ÷ old length.

Example: From 4 cm to 10 cm, the scale factor is 10 ÷ 4 = 2.5.

Learn it on: Scale (S2), Similarity (S3)

A "pizza slice" of a circle, between two radii and an arc.

Example: Sector area = (angle ÷ 360) × πr²

Learn it on: Arcs and Sectors (S3)

Half a circle.

Example: The area of a semicircle is the area of the whole circle ÷ 2.

Learn it on: Circles (S2)

A list of numbers that follows a pattern.

Example: 5, 8, 11, 14, … goes up by 3 each time.

Learn it on: Patterns and Sequences (S2)

The answer is given to you. Write every step clearly so someone can follow how you got there.

Example: Show that the volume is 452 cm³.

The digits that matter in a number, counted from the first digit that isn't zero.

Example: 0.004 72 to 2 significant figures is 0.004 7.

Don't mix up with: Decimal place

Learn it on: Significant Figures (S2)

Shapes that are enlargements of each other: same shape, matching angles equal, matching sides in the same ratio.

Learn it on: Similarity (S3)

A fraction that can't be simplified any more, because the top and bottom have no common factor except 1.

Example: 6/8 in its simplest form is 3/4.

Learn it on: Fractions (S1), Fractions, Decimals and Percentages (S1)

Write in the simplest way, by collecting like terms or cancelling.

Example: Simplify 3a + 2b + a. Answer: 4a + 2b

A way to remember the three trigonometry ratios: sin = O/H, cos = A/H, tan = O/A.

Learn it on: Right-Angled Trigonometry (S3)

Find the value of the letter that makes an equation (or inequation) true.

Example: Solve 2x + 3 = 11: x = 4

Learn it on: Equations (S1), Equations and Inequations (S3), Inequations (S2)

How far something travels in a set amount of time.

Example: 120 miles in 2 hours is a speed of 60 mph.

Learn it on: Speed, Distance and Time (S2)

How varied a set of data is. We say "more varied" or "less varied", and quote the numbers.

Example: Class B's scores were more varied, since 15 > 9.

Learn it on: Statistics (S2), Median, Quartiles & IQR (S3), Standard Deviation (S3)

The answer when a whole number is multiplied by itself.

Example: 1, 4, 9, 16, 25 are square numbers (5² = 25).

Don't mix up with: Square root

Learn it on: Types of Numbers (S1), Powers and Roots (S2)

The number that was multiplied by itself to make a square number.

Example: √49 = 7, because 7 × 7 = 49.

Don't mix up with: Square number

Learn it on: Types of Numbers (S1), Powers and Roots (S2)

A measure of how spread out data is from the mean. A bigger standard deviation means the data is more varied.

Learn it on: Standard Deviation (S3)

A way of writing very big or very small numbers as a number from 1 up to 10, multiplied by a power of 10.

Example: 45 000 = 4.5 × 10⁴ and 0.003 = 3 × 10⁻³

Learn it on: Standard Form (S2), Decimals (S2)

Give the answer. No working is needed. "Write down" means the same.

Example: State the coordinates of A.

An angle of exactly 180°: a straight line.

Example: Angles on a straight line add up to 180°.

Learn it on: Angles (S1)

The letter a formula gives you, on its own on one side.

Example: In A = l × b, A is the subject. "Make b the subject" gives b = A ÷ l.

Learn it on: Formulae (S3)

Replace the letters in an expression or formula with numbers.

Example: If a = 3, then 5a + 2 = 5 × 3 + 2 = 17.

Learn it on: Expressions and Substitution (S1), Substitution (S2), Formulae (S3)

The answer when you add numbers together.

Example: The sum of 4 and 5 is 9.

Don't mix up with: Product

Learn it on: Adding and Subtracting (S1)

Two angles that add up to 180°.

Example: 110° and 70° are supplementary.

Don't mix up with: Complementary angles

Learn it on: Angles (S1)

A table of x values and the y values worked out from a rule, used to plot a line.

Example: y = 2x + 1: x = 0, 1, 2 gives y = 1, 3, 5.

Learn it on: Straight Line (S2)

A straight line that touches a circle at just one point. It meets the radius at a right angle.

Don't mix up with: Tangent (trigonometry)

Learn it on: Angles in Circles (S3)

The trigonometry ratio tan x° = opposite ÷ adjacent.

Example: tan 40° ≈ 0.839

Don't mix up with: Tangent (circle)

Learn it on: Right-Angled Trigonometry (S3)

One part of an expression, separated from the others by + or − signs.

Example: In 3x + 2y − 5, the terms are 3x, 2y and −5.

Learn it on: Expressions and Substitution (S1), Patterns and Sequences (S2)

How long it is from one time to another. Count on to the next hour, then whole hours, then the minutes left.

Example: 09:45 to 13:20 is 3 h 35 min.

Learn it on: Speed, Distance and Time (S2), Time Zones (S2)

A part of the world that uses the same clock time. Places to the east are ahead of the UK; places to the west are behind.

Example: When it is 12:00 in the UK, it is 21:00 in Tokyo.

Learn it on: Time Zones (S2)

How much a measurement is allowed to be above or below its target, written with ±.

Example: 45 ± 1.5 g means anything from 43.5 g to 46.5 g is acceptable.

Learn it on: Tolerance (S2)

Sliding a shape without turning or flipping it: right or left, then up or down.

Example: Translate 3 right and 2 down.

Learn it on: Rotational Symmetry and Transformations (S2)

Working out the value of one (one item, one gram, £1) first, then using it.

Example: 5 pens cost £3.50, so 1 pen costs 70p.

Learn it on: Money (S2)

Value Added Tax: a tax added to the price of many things you buy. It is 20% in the UK.

Example: £350 + 20% VAT = £420

Learn it on: Percentages (S2)

A corner, where lines or edges meet. The plural is vertices. In angle ABC, the vertex is B.

Learn it on: Angles (S1)

A straight up-and-down line on a grid, with equation x = a number.

Example: x = −2

Don't mix up with: Horizontal line

Learn it on: Straight Line (S2)

The angles opposite each other where two straight lines cross. They are equal.

Example: If one angle is 40°, the angle opposite it is also 40°.

Learn it on: Angles (S1)

The amount of space inside a 3D shape, measured in cubic units.

Example: A cuboid 4 cm by 3 cm by 2 cm has volume 24 cm³.

Don't mix up with: Capacity

Learn it on: Volume (S2), Volume (S3)

Pay worked out by the hour or by the week.

Example: 35 hours × £11.40 = £399 a week.

Don't mix up with: Salary

Learn it on: Wages and Salaries (S3)

A +1 tile and a −1 tile together. They make zero, so they can be removed.

Example: 5 + (−3): three zero pairs leave 2.

Learn it on: Integers (S1)