Nodejs Utililty Methods Number Add

Number.prototype.add = function () {
    return this + [].slice.apply(arguments).reduce(function (a, b) {
            "use strict";
            return a + b;
        },0);

Number.prototype.add = function(a) {
  return this.valueOf() + a;
};
Number.prototype.subtract = function(a) {
  return this.valueOf() - a;
};
Number.prototype.multiply = function(a) {
  return this.valueOf() * a;
};
...

Number.prototype.add = function(arg){
  var r1, r2, m;
  try{r1 = this.toString().split(".")[1].length}catch(e){r1=0}
  try{r2 = arg.toString().split(".")[1].length}catch(e){r2=0}
  m = Math.pow(10, Math.max(r1, r2))
  return (this*m+arg*m)/m
Number.prototype.sub = function(arg){
  return this.add(-arg)
...

Number.prototype.add = function(n){
  return this+n
Number.prototype.subtract = function(n){
  return this-n
Number.prototype.multiply = function(n){
  return this*n
Number.prototype.divide = function(n){
  return this/n
Number.prototype.square = function(n){
  var _ = this;
  return Math.pow(_,2)
Number.prototype.add      = function(n){ return this+n }
Number.prototype.subtract = function(n){ return this-n }
Number.prototype.multiply = function(n){ return this*n }
Number.prototype.divide   = function(n){ return this/n }
Number.prototype.square   = function(){ return this*this }

Number.prototype.add      = function(n){ return this+n }
Number.prototype.subtract = function(n){ return this-n }
Number.prototype.multiply = function(n){ return this*n }
Number.prototype.divide   = function(n){ return this/n }
Number.prototype.square   = function(){ return this*this }

Number.prototype.add = function(num) {
  return this + num;
var n = 5;
assert(n.add(3) == 8, 'It works when the number is in a variable.');
assert((5).add(3) == 8, 'Also works if a number is wrapped in parentheses.');
assert(5.add(3) == 8, 'What about a simple literal?');

Number.prototype.add = function(num)
    return this+num;
};
describe("6.13", function () {
    it("It works when the number is in a variable.", function () {
         expect(n.add(3)).toEqual(8);
    });
    it("It works when the number is in a parentheses.", function () {
...

Number.prototype.add = function (num) {
  return this + num;
};
Number.prototype.subtract = function (num) {
  return this - num;
};
Number.prototype.multiply = function (num) {
  return this * num;
};
...

Number.prototype.add = function(x){
  return this + x;
};
Number.prototype.sub = function(x){
  return this - x;
};
console.log("***>(4).add(3).sub(1):", (4).add(3).sub(1));