Why does multiplying an even amount of negative numbers make a positive result?

Question

I.e., (-2)*1=-2 but (-2)*(-1)=2

In: Mathematics

Answer 1

think of the number line. positive numbers to the East of Zero and Negative Numbers to the West of Zero.
when there is a negative sign, we change the direction. When there is a positive sign, we do not change the direction.

so, when I multiply two positives, no change in direction.
when I multiple two negatives, there’s twice change in direction, hence the result is positive.

this link (from where I summarised above) explains is really at ELI5 https://www.mathsisfun.com/multiplying-negatives.html