js numbers

JavaScript
// Numbers:
1;
-99;
0.345345;

//Making variables with let:
let numberOfFriends = 1;

//Incrementing:
numberOfFriends += 3; //numberOfFriends is now 4

// Variables with const
const minimumAge = 21; //CANNOT REASSIGN!

//Booleans - true or false values
true;
false;
let isHappy = true;

//Naming Conventions
// Use upper camel-cased names:
let numberOfChickens = 6; //GOOD
// NOT THE JS WAY:
// let number_of_chickens = 6;var myNumber = 7;
var formattedNumber = ("0" + myNumber).slice(-2);
console.log(formattedNumber);
Source

Also in JavaScript: