Definition
Common multiple
A common multiple is a positive whole number that is a multiple of each of two or more numbers.
What it means
Write the positive multiples of each number and look for values that appear in every list. Those shared landing points are common multiples. There are infinitely many: after finding one, more can keep appearing.
Remember it
Two counting paths meet on the same number: that meeting point is a common multiple.
Example
Multiples of 4 include 4, 8, 12, 16, 20, 24, … Multiples of 6 include 6, 12, 18, 24, … So 12 and 24 are common multiples of 4 and 6.
Watch for
18 is a multiple of 6 but not of 4, so it is not a common multiple of 4 and 6. This glossary uses positive common multiples.
Common mix-up
A common multiple is divisible by the given numbers; a common factor divides the given numbers.
Exact meaning
A common multiple of two or more positive integers is a positive integer that is divisible by every one of them.