Why does multiplying two negative numbers equal a positive number?

Question

Why does multiplying two negative numbers equal a positive number?

In: 1210

Answer 1

the best way I’ve heard it explained is to pretend it’s instructions for walking on a number line. The first number determines whether you’re facing left or right and the second number determines whether you’re walking forward or walking backwards. so

3 * 3 = 9 you’re facing right and walking forward so you’ve walked right on the number line

-3 * 3 = -9 you’re facing left and walking forward so you’ve walked left on the number line

3 * -3 = -9 you’re facing right but walking backwards so you’ve walked left of on the number line

-3 * -3 = 9 you’re facing left but walking backwards so you’ve walked right on the number line