Download Rules of Signed Numbers

Rules of Signed Numbers
Addition:
1. If signs are the same, add the numbers and keep the same sign.
a. 7 + 8 = 15
b. -7 + -8 = -15
2. If signs are different, subtract the numbers and keep the sign of the larger number.
a. -7 + 8 = 1
b. 7 + -8 = -1
Subtraction: Change to addition and use the rules for addition –
1.
– (+)  + (-) that is minus (positive)
a. 7 – (+8) = 7 + (-8) = -1
b. -7 – (+8) = 7 + (-8) = -15
 plus (negative)
2. – (-)  + (+) that is minus (negative)  plus (positive)
a. 7 – (-8) = 7 + (+8) = +15
b. -9 – (-8) = -9 + (+8) = -1
Multiplication & Division: multiplication and division as usual with these
exceptions1. If signs are the same, answer is positive.
a. 3(4) = 12
b. -3(-4) = 12
c. -12 ÷ (-4) = 3
2. If signs are different, answer is negative.
a. -7(8) = -56
b. 12 ÷ (-4) = -3