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Notes on Subtracting Integers

 

Rule: Subtracting integers is the same as adding integers except for one additional step:

 

Step 1: Change the sign of the second number to its opposite and change the operation to addition.

Step 2: Follow the same rules as addition.

 

Example: -4 (-8)

Step 1: -4 + (+8)

Step 2: -4 + 8 = +4 (different signs, subtract keep sign of larger absolute value)

 

Note: Adding a positive is the same as subtracting a negative.

Example: 4 + 2 = 6 and 4 (-2) = 6

Note: Adding a negative is the same as subtracting a positive.

Example: 8 + (-3)= 5 and 8 (+3) = 5

 

These are called additive inverses:

The addition property of opposites says that

a + (-a) = 0