Question

What is (-8)(5)?

Answer 1

-40

Answer 2

Multiply 8 by 5. Then in multiplication and division, two equal signs make a positive, and two different signs make a negative. Since -8 and 5 have different signs, the answer is negative.
8(5) = 40
(-8)(5) = -40

Answer 3

If you want to be able to get this answer yourself, imagine you have an $8,- debt.
You keep writing checks. At a certain moment your debt is 5 times the original one, so it is $40. That explains -8*5=-40.