What is an integer?
The word integer is not in the primary curriculum, but whole numbers and negative numbers are (Years 4 to 6), and many 11+ papers use the word. Below: what it means, a worked example, the mistake to watch for and an 11+ question.
The answer
An integer is a whole number, positive, negative or zero, with no fraction or decimal part.
What it means
−3, 0, 7 and 250 are all integers. 2.5 and ½ are not, because they have a part that is less than one whole.
On a number line, the integers are the marks at every whole number, going on for ever in both directions.
A worked example
Which of these are integers: 4, −2, 0.5, 0, 3½, −10?
- 0.5 and 3½ have parts of a whole, so they are not integers.
- The integers are 4, −2, 0 and −10.
The common mistake
Thinking negative numbers or zero cannot be integers. They are whole numbers too, so −10 and 0 are integers.
How it comes up in the 11+
How many integers are greater than −3 and less than 4?
Answer: 6
- List them: −2, −1, 0, 1, 2, 3.
- −3 and 4 themselves are not included, because the numbers must be greater than −3 and less than 4.
- That is 6 integers.
Related words and practice
More maths words
Questions parents ask
Is 0 an integer?
Yes. Zero is a whole number, so it is an integer. It is neither positive nor negative.
Is a fraction an integer?
Only when it is equal to a whole number. 8/4 = 2, so it is an integer. ¾ is not.
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.