ADDING and SUBTRACTING INTEGERS
INTEGER – all positive and negative whole numbers
ABSOLUTE VALUE – the distance a number is away from zero. So in practice "absolute value" means
to remove any negative sign in front of a number, and to think of all numbers as positive
ADDITION:
There are certain rules to remember when adding integers.
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When adding positive integers, the sum will be positive. (This is the same addition you have
always done.)
(+5) + (+5) = +10
When adding two negative integers, just add the two integers, and the sum will be negative.
(-8) + (-16) = -24
When adding integers with different signs (one positive and one negative), follow these steps:
1. Subtract the number with smallest absolute value from the number with largest absolute
value,
2. The answer gets the sign of the integer with the largest absolute value.
For example, (+5) + (-10) = I would subtract, 10 – 5 = 5. 10 has a larger absolute value so the answer
would be -5. Therefore (+5) + (-10) = -5
In review:
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Positive + positive means add the numbers, your answer is positive
Negative + negative means add the numbers, your answer is negative
Positive + negative means subtract the numbers, your answer will have the sign of the largest
number
SUBTRACTION:
You DO NOT have to learn a new set of rules for Subtracting Integers;
1. Change all subtraction problems to addition and apply addition rules.
2. Change the sign second number (number being subtracted) to the opposite
- If second number is positive, it becomes negative
- If second number is negative, it becomes positive
For example, 8 – (-2), change the minus to addition and -2 becomes +2, so 8 + 2 = 10.
-3 – (+7)
-2 – (-10)
5-7
-3 + (-7) = -10
-2 + 10 = 8
5 + (-7) = -2