<?php
function round_multiple10_up($num) {
	$mod = $num % 10;
	
	if ($mod !== 0)
		return (10 - $mod) + $num;
	
	return $num;
}

function round_multiple10_down($num) {
	$mod = $num % 10;
	
	if ($mod !== 0)
		return $num - $mod;
		
	return $num;
}


$test = 135;

echo round_multiple10_up($test);
echo PHP_EOL;
echo round_multiple10_down($test);