Another non-module way is to use sprintf.

@num = (6, 5.3, 8.5, 9.5000000001, 3.84, 4.51);
foreach $num (@num) {
   print qq{original: $num\n};
   $new = sprintf "%.0f\n",$num;
   print qq{new: $new};
}
[download]

will produce

original: 6
new: 6
original: 5.3
new: 5
original: 8.5
new: 8
original: 9.5000000001
new: 10
original: 3.84
new: 4
original: 4.51
new: 5
[download]

Not quite right for the 8.5, but it is close for the rest, and that can be compared differently.

Originally posted as a Categorized Answer.