Logic Brain Gym — Solutions

🔥 Challenge 1 — FizzBuzz

Rules recap:

• Multiple of 3 → Fizz
• Multiple of 5 → Buzz
• Multiple of 3 & 5 → FizzBuzz

let number = 15;

if (number % 3 === 0 && number % 5 === 0) {
  console.log("FizzBuzz");
} else if (number % 3 === 0) {
  console.log("Fizz");
} else if (number % 5 === 0) {
  console.log("Buzz");
} else {
  console.log(number);
}
          

Why this order matters:
The combined condition must be checked first. Otherwise, JavaScript will exit early and your logic breaks.

🔥 Challenge 2 — Odd / Even Loop

Loop from 1 to 10:

• Even numbers → “Even”
• Odd numbers → “Odd”

for (let i = 1; i <= 10; i++) {
  if (i % 2 === 0) {
    console.log(i + " Even");
  } else {
    console.log(i + " Odd");
  }
}
          

This challenge checks three things: looping, modulo, and clean conditional thinking.

🔥 Challenge 3 — Login Simulation

Conditions:

• Correct username
• Correct password
• Error message if invalid

let inputUsername = "admin";
let inputPassword = "12345";

let correctUsername = "admin";
let correctPassword = "12345";

if (inputUsername === correctUsername && inputPassword === correctPassword) {
  console.log("Login successful 👋");
} else {
  console.log("Username or password is wrong ❌");
}
          

This is a simplified version of real authentication logic. Same concept, different scale.

🚀 Bonus — More Detailed Validation

Cleaner feedback for users:

if (inputUsername !== correctUsername) {
  console.log("Username not found");
} else if (inputPassword !== correctPassword) {
  console.log("Wrong password");
} else {
  console.log("Login successful");
}
          

Same logic. Better UX.