There's an easy method: 
sub round_to_halves {
    return 0.5 * (int(2*$_[0]));
}
my $num = 1.6;
print round_to_halves($num), "\n";

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In reply to Re: Round down to '.5' or '.0' by moritz
in thread Round down to '.5' or '.0' by awohld

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