// JavaScript
let age = 25;                    // number
const price = 19.99;             // number
var isActive = true;             // boolean
let name = "Alice";              // string
const numbers = [1, 2, 3];       // array
let scores = { Alice: 95, Bob: 87 };  // object
let nullable = null;             // null
let undefinedVar;                // undefined