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Math Notes » Add/Subtract Integers
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Add/Subtract Integers
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Add/Subtract Integers
| Do the numbers have the SAME SIGN? | | YES - | Same Signs:
Find the SUM:
| | NO - | Different signs:
Find the DIFFERENCE:
| (-3) + (-6) = (-9)
(+4) + (+5) = (+9)
| | (+5) + (-7) = (-2)
(-4) + (+6) = (+2)
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Either way: Keep the sign of the LARGER* number. | * "LARGER" is used here as a quick (but mathematically imprecise) way to describe the integer with the greater Absolute Value (ie. distance from zero). In each of the examples above, the SECOND integer has a greater Absolute Value.
First, change the SUBTRACTION problem to an ADDITION problem; Then, follow the rules (above) for solving the new ADDITION problem. (-6) - (+2) = | First, copy the problem exactly. 1. The first number stays the same. 2. Change the operation. 3. Switch the NEXT SIGN. 4. Follow the rules for addition. | | (-6) - (+2) = (-6) (-6) + (-6) + (-2) (-6) + (-2) = (-8) | Subtract means:
Add the opposite.
| (+2) - (-6) =
(+2) + (+6) = (+8)
| Subtract means:
Add the opposite.
| (-7) - (-3) =
(-7) + (+3) = (-4)
| Subtract means:
Add the opposite.
| (+4) - (+9) =
(+4) + (-9) = (-5) |
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