Rules for Adding & Subtracting

Integers

Any SUBTRACTION problem can be expressed as an ADDITION problem by…

“ADDING THE OPPOSITE”

16 – 10 becomes? 16 + (-10)

-26 – 13 becomes? -26 + (-13)

Adding & Subtracting Integers

15 – (-22) becomes? 15 + (+22)

-42 – (-14) becomes? -42 + (+14)

METHOD 1 – SAME SIGN

When adding integers with the SAME SIGN(i.e. both positive or both negative)

1. Make both integers positive(absolute value!)

2. ADD the numbers

3. If the original integers were POSITIVE, the final answer is POSITIVE

4. If the original integers were NEGATIVE, the final answer is NEGATIVE

Example:

-122 + (-234)

122+ 234 356

Nope!

Yup!

Answer: -356

METHOD 2 – DIFFERENT SIGN

When adding integers with DIFFERENT SIGNS

1. Make both integers positive(absolute value!)

2. SUBTRACT the smaller from the larger

3. If the larger integer was POSITIVE, the final answer is POSITIVE

4. If the larger integer was NEGATIVE, the final answer is NEGATIVE

Example:

122 + (-234)

234– 122 112

Nope!

Yup!

Answer: -112