To add integers, move right on the number line for positive numbers and left for negative numbers. If the signs are the same, keep the sign when adding the digits. If signs differ, find the difference and keep the sign of the larger digit. To subtract, move in the opposite direction as when adding. For multiplication and division, if signs are the same the product is positive and if signs differ the product is negative.

1. Adding integers on a number line:
Move right on a number line to add a positive integer.
Move left on a number line to add a negative integer
 If the signs are the same, add the digits and keep the sign.
 If the signs are different: find the difference, take the sign of the larger digit.
Subtracting integers on a number line:
Move left on a number line to subtract a positive integer.
Move right on a number line to subtract a negative integer.
 Keep, Change, Change
 If the signs are the same, add the digits and keep the sign.
 If the signs are different: find the difference, take the sign of the larger digit.
Multiplying & Dividing Rules:
If the signs are the same, the product is positive
If the signs are different, the product is negative