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lcm

mathintermediate

Returns the least common multiple of two or more numbers.

Use the greatest common divisor (GCD) formula and the fact that lcm(x,y) = x * y / gcd(x,y) to determine the least common multiple. The GCD formula uses recursion.

function lcm(...$numbers)
{
  $ans = $numbers[0];
  for ($i = 1, $max = count($numbers); $i < $max; $i++) {
    $ans = (($numbers[$i] * $ans) / gcd($numbers[$i], $ans));
  }

  return $ans;
}