I think, then, that you want 
$n + ($m - $n % $m) % $m;

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That ensures that what you are subtracting from $m is not larger than $m, and the result is the same, modulo $m.

In Perl, modulo works as it is supposed to. :-) The result is between zero and the right operand. In Java, it's broken. This allows us to simplify the expression a bit further: 

$n + -$n%$m;

[download]
Caution: Contents may have been coded under pressure.

In reply to Re^4: Best way to make sure a number is an even multiple of another? by Roy Johnson
in thread Best way to make sure a number is an even multiple of another? by demerphq

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