**Important Concepts and Formulas**

1. Numbers below zero are negative
numbers.

2. Negative numbers together with whole
numbers are called integers … –3, –2, –1, 0, 1, 2, 3, … are integers.

3. The numbers 1, 2, 3, 4, … are
positive integers and –1, –2, –3, … are negative integers.

4. The number 0 is neither positive nor
negative.

5. The absolute value of an integer is
always positive and is equal to the numerical value of that integer.

6. Every positive integer is greater
than 0 and every negative integer is smaller than 0.

7. The greatest negative integer is −1
and the smallest positive integer is 1.

8. When we add integers of the same
sign, then we add and put the same sign in the answer.

9. To add two integers with unlike signs, we find the difference of their absolute values and place the sign of the integer having the larger absolute value.

9. To add two integers with unlike signs, we find the difference of their absolute values and place the sign of the integer having the larger absolute value.

10. To subtract an integer from another,
we add the additive inverse of the number to be subtracted.