If a is an integer, when is a/b always equal to an integer?

A must be equal to b so like a multiple of b. at least or - b because it works

A must be equal to b or be a multiple of b or - b in order to be an integer

example 5/5 is an integer (1)

60/5 is an integer (12) because 60 is a multiple of 5

-30/5 is an integer (-6) because - 30 is a multiple of - 5