A
- Addition
- Combining two or more numbers to find their total, or sum. The inverse of subtraction.
- Arithmetic
- The branch of maths dealing with the four operations: addition, subtraction, multiplication and division.
- Array
- An arrangement of objects in equal rows and columns, used to make multiplication visible, 3 rows of 4 shows 3 × 4 = 12.
B
- Bridging through ten
- A mental strategy where you add to the next multiple of ten first, 8 + 5 becomes 8 + 2 + 3, to make the calculation easier.
C
- Column method
- A written method for adding, subtracting, multiplying or dividing by lining up digits in place-value columns.
- Commutative
- A property meaning the order doesn't change the result: 3 × 4 = 4 × 3 and 2 + 5 = 5 + 2. Addition and multiplication are commutative; subtraction and division are not.
D
- Denominator
- The bottom number of a fraction, showing how many equal parts the whole is divided into. In 3/4 the denominator is 4.
- Difference
- The result of a subtraction, the gap between two numbers. The difference between 9 and 4 is 5.
- Digit
- A single number symbol from 0 to 9. The number 254 has three digits.
- Divisor
- The number you are dividing by. In 20 ÷ 4 = 5, the divisor is 4.
- Doubles
- Adding a number to itself, such as 6 + 6 = 12. Knowing doubles unlocks near-doubles like 6 + 7.
E
- Equivalent fractions
- Different fractions that represent the same amount, such as 1/2 and 2/4.
- Estimate
- A sensible approximate answer, often found by rounding, used to check whether a calculation is reasonable.
F
- Factor
- A whole number that divides exactly into another. The factors of 12 are 1, 2, 3, 4, 6 and 12.
- Fluency
- The ability to recall number facts quickly and accurately, and to use flexible strategies, the goal of quick-fire practice.
- Fraction
- A number representing part of a whole, written as a numerator over a denominator, such as 3/4.
I
- Inverse operation
- An operation that undoes another. Subtraction is the inverse of addition; division is the inverse of multiplication.
K
- Key Stage 1 (KS1)
- In England, the school years for children aged 5–7 (Years 1 and 2).
- Key Stage 2 (KS2)
- In England, the school years for children aged 7–11 (Years 3 to 6).
M
- Mental maths
- Calculating in your head using recalled facts and strategies, without written methods or a calculator.
- Multiple
- The result of multiplying a number by a whole number. Multiples of 5 are 5, 10, 15, 20 and so on.
- Multiplication
- Repeated addition of equal groups, 4 × 3 means four groups of three. The inverse of division.
N
- Number bond
- A pair of numbers that add to a given total, such as 7 + 3 = 10. Bonds to 10, 20 and 100 are core facts.
- Number line
- A line marked with numbers in order, used to count, compare, add and subtract.
- Numerator
- The top number of a fraction, showing how many equal parts you have. In 3/4 the numerator is 3.
P
- Partitioning
- Splitting a number into parts, usually by place value, 46 becomes 40 and 6, to make calculating easier.
- Place value
- The value a digit has because of its position. In 254 the 5 means five tens, not five.
- Product
- The result of a multiplication. The product of 6 and 7 is 42.
Q
- Quotient
- The result of a division. In 20 ÷ 4 = 5, the quotient is 5.
R
- Recall
- Retrieving a fact instantly from memory rather than working it out, the aim of fluency practice.
- Regrouping
- Exchanging between place-value columns when adding or subtracting, sometimes called carrying or borrowing.
- Remainder
- The amount left over when one number does not divide exactly into another. 17 ÷ 5 = 3 remainder 2.
- Rounding
- Replacing a number with a nearby, simpler one, 47 rounds to 50 to the nearest ten.
S
- Square number
- The result of multiplying a whole number by itself, such as 5 × 5 = 25. Written 5².
- Subitising
- Instantly recognising how many objects there are without counting, usually up to about five.
- Subtraction
- Taking one number away from another to find the difference. The inverse of addition.
- Sum
- The total when numbers are added together.
T
- Times table
- The set of multiplication facts for a number, such as the 6 times table: 6, 12, 18, 24…