How to get a random number in JavaScript

Question

I want to make a math game involving random numbers but I don't know how to get random numbers.
If that is not possible how to select from an array?

Answer 1

--Random number: (between 0 and 1)
Math.random()

--Random number between 0 and what number you want:

Math.floor(Math.random()*your number)

--Random element from array:

array[Math.floor(Math.random()*array.length)]