How is this code return at -2 to 2 number?

Question

How can this return a number between -2 and 2

var number = Math.random() * 4 - 2;

Answer 1

The method Math.random() gives you a decimal number between 0 and 1. If it returns, 0.00001, you'll get 0.00001 * 4 - 2 = 0.00004 - 2 = -1.99996

A pseudo-random number in the range 0 to less than 1 (inclusive of 0, but not 1) with approximately uniform distribution over that range — which you can then scale to your desired range.