random number generate (with + without) range in javascript

randomGenerator.js

// how to create random numbers
// random numbers

var rand = Math.random();   //will create random number between 0 - 1
console.log(rand);


// random numbers from 0 - rand1

var rand1 = 6;
var randomNumberZeroToRand1 = Math.floor(Math.random()*rand1);
console.log(randomNumberZeroToRand1);


// random number from rand2 to rand3

var rand2 = 100;
var rand3 = 350;

var randomNumberRand2ToRand3 = rand2 + Math.floor(Math.random()*(rand3-rand2));
console.log(randomNumberRand2ToRand3);