You can't really distinguish @nums which round to the same. If you need to tell them apart, don't round them. Ignoring that problem, you can construct a hash of short_nums to nums,

my %unround;
@unround{@short_nums} = @nums;
my @new_array = map {$unround{$_}} grep {exists $unround{$_}} @found;
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That construction makes the last occurence of nearly equal @nums be returned.

After Compline,
Zaxo