You can use the following rules to help you add, subtract, multiply, or divide positive and negative numbers.
Adding Rules:
Positive + Positive = Positive: 5 + 6 = 11
Negative + Negative = Negative: (- 5) + (- 4) = – 9
Sum of a negative and a positive number: Use the sign of the larger number and subtract
(- 7) + 4 = -3
6 + (-9) = – 3
(- 3) + 7 = 4
5 + ( -3) = 2
Subtracting Rules:
Negative – Positive = Negative: (- 5) – 3 = -5 + (-3) = -8
Positive – Negative = Positive + Positive = Positive: 5 – (-3) = 5 + 3 = 8
Negative – Negative = Negative + Positive = Use the sign of the larger number and subtract (Change double negatives to a positive)
(-5) – (-3) = ( -5) + 3 = -2
(-3) – ( -5) = (-3) + 5 = 2
Multiplying Rules:
Positive x Positive = Positive: 3 x 2 = 6
Negative x Negative = Positive: (-2) x (-8) = 16
Negative x Positive = Negative: (-3) x 4 = -12
Positive x Negative = Negative: 3 x (-4) = -12
Dividing Rules:
Positive ÷ Positive = Positive: 12 ÷ 3 = 4
Negative ÷ Negative = Positive: (-12) ÷ (-3) = 4
Negative ÷ Positive = Negative: (-12) ÷ 3 = -4
Positive ÷ Negative = Negative: 12 ÷ (-3) = -4