Integers don't include fractions or decimal points, they're always whole numbers. Numbers like 2.5 or 7/8 are not considered integers.
Pro Tip 2/3
Zero Inclusive
Remember that zero is an integer too, neither positive nor negative. Don't forget to include 0 when listing integers.
Pro Tip 3/3
No In-Betweens
Integers are not 'between' numbers; they are exact values with no in-betweens. The numbers 3 and 4 are integers, but there's nothing 'integer-ish' about 3.5.