Download Integer Operations Tip Sheet

1
Math Resources
Integer Operations Tip Sheet
Addition
SAME SIGNS
DIFFERENT SIGNS
(of two numbers)
(both numbers positive, or both
numbers negative)
(one number negative, one number
positive)
When ADDING two numbers When ADDING two numbers
with the SAME SIGN:
with DIFFERENT SIGNS:
 Answer
takes
the
 Answer takes the sign of
common sign of the two
the number with the
numbers
larger absolute value
 Just ADD the numbers
 Just SUBTRACT the
numbers
 (or Add the numbers
and Keep the sign!)
 (or Subtract the numbers
and keep the sign of the
-7 + (-18) = -25
larger number)
-3 + 12 = +9
14 + (– 20) = -6
Subtraction
(of two numbers)
REWRITE as Addition
When
SUBTRACTING
Integers, be sure to change the
signs by:
 Writing the leftmost
number,
 Changing
the
subtraction symbol to
an addition symbol
 Writing the opposite
of the rightmost
number
 Apply the Addition
Rules to solve!
 Or (Apply the Keep
Change Change or
Copy Change Change
Rule)
Examples
-17 – 24 = -17 + (-24) = -41
Keep Change Change
-6 – (-4) = - 6 + (+4) = -2
* Note: Positive Numbers are rarely written with (+) signs, they are written here to
emphasize that the number is positive.
2
Math Resources
SAME SIGN
Multiplication &
When you Multiply (or Divide) two numbers with
Division
the same sign the answer is POSITIVE!
(of two numbers)
9  5   45
7  2    14
81  27
3
24   8
3
DIFFERENT SIGN
When you Multiply (or Divide) two numbers with
different signs the answer is NEGATIVE!
8 2   16
(5)(3)  15
36   3
12 
72   9
8 
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