Operations on positive and negative numbers
Mathematical rules for dealing with operations involving positive and negative numbers.
| Addition (+) |
| Positive + Positive = Positive | 7 + 3 = 10 |
| Negative + Negative = Negative | – 7 + (-3) = – 10 |
| Positive + Negative(use the larger number and its sign, subtract) subtract the smaller number from the larger number, then use the sign of the larger number in the answer. | – 3 + 7 = + (7 – 3) = 4 7 + (- 3) = 4 |
| Negative + Positive (use the larger number and its sign, subtract)
subtract the smaller number from the larger number, then use the sign of the larger number in the answer. |
– 7 + 3 = – (7- 3) = – 4
3 + (-7) = – (7- 3) = – 4 |
| Subtraction (-) |
| Negative – Positive = Negative | -7 – (+ 3) = – (7 + 3) = – 10 |
| Positive – Negative = Positive | 7 – (-3) = 7 + 3 = 10 |
| Negative – Negative = Negative + Positive
(use the larger number and its sign, subtract) subtract the smaller number from the larger number, then use the sign of the larger number in the answer. |
– 3 – (- 7) = – 3 + 7 = + (7 – 3) = 4 – 7 – (- 3) = – 7 + 3 = – (7 – 3) = – 4 |
| Multiplication (x) |
|
Positive x Positive = Positive (+) ⋅ (+) -> (+) |
7 x 3 = 21 |
|
Negative x Negative = Positive (-) ⋅ (-) -> (+) |
– 7 x (-3) = 21 |
|
Negative x Positive = Negative (-) ⋅ (+) -> (-) |
– 3 x 7 = – 21 – 7 x 3 = – 21 |
|
Positive x Negative = Negative (+) ⋅ (-) -> (-) |
7 x (- 3) = – 21 3 + (-7) = – 21 |
| Division (÷) |
|
Positive ÷ Positive = Positive (+) : (+) -> (+) |
10 : 2 = 5 |
|
Negative ÷ Negative = Positive (-) : (-) -> (+) |
– 10 : (-2) = 5 |
|
Negative ÷ Positive = Negative (-) : (+) -> (-) |
– 10 : 2 = – 5 |
|
Positive ÷ Negative = Negative (+) : (-) -> (-) |
10 : (- 2) = – 5 |
