Problem

2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder.

What is the smallest positive number that is evenly divisible by all of the numbers from 1 to 20?

Solution

$i = 2;

for ($j = 1; $j <= 20; $j++) {
  if ($i % $j > 0) {
    for ($k = 1; $k <= 20; $k++) {
      if (($i * $k) % $j == 0) {
        $i *= $k;
        break;
      }
    }
  }
}

echo $i;