How can you tell if the sum will be positive, neagitive, or zero

If both numbers are positive, the sum will be positive.

If both numbers are negative, the sum will be positive.

If one number is negative, and one is positive, the sum will be negative.

If one number is zero, the sum will be zero.

Examples:

6 x 2 = 12

-6 x - 3 = 18

-7 x 2 = - 14

9 x 0 = 0