Adding Integers
If the numbers that you are adding have the same sign, then add the numbers and keep the sign.
Example:
-5 + (-6) = -11
Adding Numbers with Different Signs
If the numbers that you are adding have different (opposite) signs, then SUBTRACT the numbers and take the sign of the number with the largest absolute value.
Examples:
-6 + 5= -1
12 + (-4) = 8
Subtracting Integers
When subtracting integers, I use one main rule and that is to rewrite the subtracting problem as an addition problem. Then use the addition rules.
When you subtract, you are really adding the opposite, so I use theKeep-Change-Change rule.
The Keep-Change-Change rule means:
Keep the first number the same.
Change the minus sign to a plus sign.
Change the sign of the second number to its opposite.
Example:
12 - (-5) =
12 + 5 = 17
Multiplying and Dividing Integers
The great thing about multiplying and dividing integers is that there is two rules and they apply to both multiplication and division!
Again, you must analyze the signs of the numbers that you are multiplying or dividing.
The rules are:
If the signs are the same, then the answer is positive.
If the signs are different, then then answer is negative.
