Math.random() // Returns number from 0 to 1.
Math.floor(Math.random() * max) // Return number from 0 to max minus 1
// Example
Math.floor(Math.random() * 10) // Return number from 0 to 9
// Add a +1 to return a number from 0 to max
Math.floor(Math.random() * 10) + 1 // Returns Number from 1 to 10
// To have a min and max
Math.floor(Math.random() * (max - min)) + min
// Example
Math.floor(Math.random() * (20 - 10)) + 10