1. Natural Numbers The Natural or counting numbers are denoted by N and are defined by:

2. Integers Integers are denoted by the letter Z and are defined by the following set:

3. Rational Numbers The set of Rational numbers is denoted by the letter Q and is given by:

4. Rule for multiplying or dividing two signed numbers If the signs of the two numbers is the same, the result is positive If the signs of the two numbers are different, the result is negative

5. Absolute Value The absolute value of a number is always non-negative. Read through examples 5 – 9 on pages 7-11 in the text