freeCodeCamp Challenge Guide: Problem 5: Smallest multiple

Problem 5: Smallest multiple

Problem Explanation

  • In this challenge we need to find the LCM of 1 to n numbers.
  • To find LCM of a number we use the following formula:
    • lcm
  • To find GCD (Greatest Common Divisor) of two number we use Euclidean algorithm.
  • Once we get LCM of two numbers, we can get LCM of the numbers from 1 to n.


Solution 1 (Click to Show/Hide)
//LCM of two numbers
function lcm(a, b) {
  return (a * b) / gcd(a, b);

//Euclidean recursive algorithm
function gcd(a, b) {
  if (b === 0) return a;
  return gcd(b, a % b);

function smallestMult(n) {
  let maxLCM = 1;

  //Getting the LCM in the range
  for (let i = 2; i <= n; i++) {
    maxLCM = lcm(maxLCM, i);
  return maxLCM;

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