SUBTRACTING INTEGERSSUBTRACTING INTEGERS

Math 7

Subtracting IntegersSubtracting Integers

Learn the rules for subtracting integers

Recall rules for adding integers

Several examples

Rules for Subtracting IntegersRules for Subtracting Integers

There are two rules to remember:

1) Add the Opposite

2) Follow Rules for Adding

Add the OppositeAdd the Opposite

This means that we are going to change this problem to an addition problem.

To legally do this, you must change the subtraction sign to addition, and then change the sign on the 2nd integer to its opposite. (DO NOT MESS WITH THE FIRST INTEGER)

Follow Addition RulesFollow Addition Rules

Since you changed the subtraction sign into an addition sign, you have now created an addition problem, which we already learned how to do. So, we must follow the rules for addition.

Recall Addition RulesRecall Addition Rules

If signs are the same, add and keep the same sign.

If signs are different, ask yourself:1) What are there more of?

2) How many more?

Recap for Subtraction of Recap for Subtraction of IntegersIntegers

1) Add the Opposite

2) Follow rules for addition of integers

Several ExamplesSeveral Examples

-3 – (-9) = -25 – 30 =

17 – (-12) = 32 – (-17) =

-23 – 11 = -38 – (-12) =

18 – 23 = 100 – 64 =

ANY QUESTIONS???ANY QUESTIONS???

HOMEWORK: Subtracting Integers

Worksheet