Learn it
- Same signs: add the absolute values and keep the sign. −4 + (−6) = −10.
- Different signs: subtract the absolute values and keep the sign of the number with the larger absolute value. −9 + 5 = −4.
- Subtracting means adding the opposite: 3 − 8 = 3 + (−8) = −5, and 2 − (−7) = 2 + 7 = 9.
Think of a number line: adding a positive moves right, adding a negative moves left.
Worked examples
Example 1
Find −12 + 7.
- Different signs: 12 − 7 = 5
- −12 has the larger absolute value, so the answer is negative
Answer: −5
Example 2
Find −3 − (−10).
- Subtracting a negative means adding the opposite
- −3 + 10 = 7
Answer: 7
Practice
Try these on paper first, then check your work.
- −8 + (−5)
- 15 + (−20)
- −6 − 4
- 0 − (−9)
Show the answer key
- −13
- −5
- −10
- 9