Creating a number is easy, it can be done just like for any other variable type using the var keyword.

Numbers can be created from a constant value:

// This is a float:
var a = 1.2;

// This is a integer:
var b = 10;

Or from the value of another variable:

var a = 2;
var b = a;

Create a variable x which equals 10 and create a variable y which equals a.

var a = 11;

var a = 11;

var x = 10;
var y = a;

assert(x === 10 && y === a);