Addition, subtraction, multiplication.
Addition: The addition of two integers produces another integer.
Subtraction: The subtraction of two integers produces another integer.
Multiplication: The product of two integers is an integer.
Division between two integers can produce a rational number that is not in the set of integers e.g. 1/3
This only includes the four basic arithmetic operations, you can include exponentiation and the modulo operation if you want to for the same reasons as above.
