Arithmetic : Properties of Integers and Numbers

Properties of the Integers 0 and 1

If 0 is added to or subtracted from any number, the number remains unchanged.
Zero is therefore called the identity element for addition and subtraction.
If 0 is multiplied by any number, the product is 0.
If 0 is divided by any number (other than 0), the quotient is 0.
Division by 0 is not defined because it has no meaning.

If any number is multiplied or divided by 1, the number remains unchanged.
One is therefore called the identity element for multiplication and division.