Glossary
integer
An integer is a whole number — positive, negative or zero: …, −2, −1, 0, 1, 2, …. Nothing with a fractional part is one, so 3.5 is not an integer and neither is 1/2.
An integer is a whole number with no fractional part. The integers are the counting numbers, their negatives, and zero: … −3, −2, −1, 0, 1, 2, 3 …. 7 and −12 are integers; 1/2, 3.5 and −0.75 are not.
The distinctions that questions test are all about the boundaries. Zero is an integer. A fraction written as a decimal that comes out even is still not an integer unless the value is whole — 6/3 is 2 and so is an integer, while 7/2 is 3.5 and is not. A decimal such as 4.0 has the value of an integer but is written as a decimal, so read what the question is asking about the form as well as the value.
Integers are the set that the arithmetic rules are usually stated for. Adding, subtracting and multiplying two integers always gives an integer; dividing them does not, which is where fractions come from. Prime numbers, factors and multiples are all defined on integers, and a negative times a negative is positive — a rule that only makes sense once you accept numbers below zero.
Taught in
Related terms
- prime number — A prime number has exactly two factors: 1 and itself. 2, 3, 5, 7 and 11 are prime; 1 is not, and 9 is not because 3 divides it.
Source: Official ASVAB — subtest descriptions (what each subtest asks) and the CAT-ASVAB scored-question counts (accessed 2026-09)