int(1234567 / 10000) = 123
1234567 % 10000      = 4567

##</code><code>##

$x = int($x/$d) * $d + $x%$d

##</code><code>##

1234567
= 123 * 10000 + 4567
= int(1234567/10000) * 10000 + 1234567%10000