JavaScript Math Object: Built-In Methods for Mathematical Operations

// ❌ Never do this:const math = new Math();    // TypeError: Math is not a constructor
// ✅ Just use it directly:Math.round(4.6);            // 5

const n = 4.5;
Math.round(n);
// 5   — nearest integer (4.4 → 4, 4.5 → 5, 4.6 → 5)Math.floor(n);    // 4   — always rounds DOWNMath.ceil(n);     // 5   — always rounds UPMath.trunc(n);    // 4   — just CHOPS the decimal part off

Math.floor(-4.5);
// -5 😱  (floor goes DOWN — toward −∞)Math.trunc(-4.5);     // -4 ✅  (trunc just chops)Math.ceil(-4.5);      // -4 😮  (ceiling goes UP — toward +∞)Math.round(-4.5);     // -4     (rounds toward +∞ on .5)

function roundTo(num, decimals) {
  const factor = 10 ** decimals;
  // Lesson 12's exponent!   return Math.round(num * factor) / factor;}
  roundTo(3.14159, 2);
  // 3.14 ✅roundTo(3.14159, 3);    // 3.142roundTo(19.995, 2);     // 20 (watch for float dust — Lesson 12!)

Math.max(5, 12, 8, 3);
// 12 — the biggestMath.min(5, 12, 8, 3);      // 3  — the smallestMath.abs(-42);              // 42 — distance from zeroMath.abs(42);               // 42 — positive stays positive

const scores =[45, 92, 67, 88];
Math.max(scores);
// NaN ❌ — an array isn't numbers!
Math.max(...scores);
// 92 ✅ — spread from Lesson 14 saves the day!Math.min(...scores);     // 45 ✅

function clamp(value, min, max) {
  return Math.min(Math.max(value, min), max);
}clamp(150, 0, 100);
// 100 — capped at the top ✅clamp(-20, 0, 100);    // 0   — floored at the bottom ✅clamp(55, 0, 100);     // 55  — inside range, untouched ✅

Math.pow(2, 10);
// 1024 — 2 to the power 102 ** 10;              // 1024 — the modern operator (Lesson 12) — prefer this ✨
Math.sqrt(144);
// 12  — square rootMath.cbrt(27);        // 3   — cube root (3×3×3 = 27)
Math.hypot(3, 4);
// 5   — √(3² + 4²) — the Pythagorean shortcut! 📐

// Distance between player (0,0) and enemy (3,4):const distance = Math.hypot(3 - 0, 4 - 0);   // 5 — game devs love this 🎮

Math.random();
// 0.3829174…Math.random();    // 0.9102837… — different every call

const n = Math.floor(Math.random() * 10);
// 0–9

const n = Math.floor(Math.random() * 10) + 1;
// 1–10

function randomInt(min, max) {
  return Math.floor(Math.random() *(max - min + 1)) + min;
}randomInt(1, 6);
// dice roll: 1–6 🎲randomInt(50, 100);   // 50–100randomInt(2000, 2026); // a random year

const prizes =["🎁 Gift card", "🎧 Headphones", "🍕 Free pizza", "📚 Ebook"];
const randomPrize = prizes[Math.floor(Math.random() * prizes.length)];
console.log(`You won: ${randomPrize}!`);

Math.PI;
// 3.141592653589793 — circle math 🟣Math.E;         // 2.71828… — the natural constant
// Circle calculations:const radius = 7;const area = Math.PI * radius ** 2;              // 153.94 — πr²const circumference = 2 * Math.PI * radius;      // 43.98 — 2πr

Math.sign(-10);
// -1  — negativeMath.sign(0);       //  0  — zeroMath.sign(42);      //  1  — positive (great for direction logic!)
Math.log10(1000);
// 3   — base-10 logMath.log2(8);       // 3   — base-2 log (2³ = 8)

// 🎲 Dice Battle — two players, best of the Math object!
function rollDice() {
  return Math.floor(Math.random() * 6) + 1;
  // Recipe ③: 1–6
}function playRound(player1, player2) {
  const roll1 = rollDice();
  const roll2 = rollDice();
  console.log(`${player1} rolled: ${roll1} 🎲`);
  console.log(`${player2} rolled: ${roll2} 🎲`);
  const winner = Math.sign(roll1 - roll2);
  // sign() as a judge! ⚖️
  if (winner === 1) {
    console.log(`🏆 ${player1} wins by ${Math.abs(roll1 - roll2)}!`);
  } else if (winner === -1) {
    console.log(`🏆 ${player2} wins by ${Math.abs(roll1 - roll2)}!`);
  } else {
    console.log("🤝 It's a tie! Roll again…");
  }
}playRound("Priya", "Amit");

Priya rolled: 4 🎲Amit rolled: 6 🎲🏆 Amit wins by 2!