There is a easy way to remedy this...

 for my $text (qw/first third thirteenth twentyfirst twentysecond oneh
+undredone onehundredtwelve onehundredeleven/) {

 my $number = str2nbr($text);

 my $sufix = 'th';

 if ( $number =~ /^1$/ or $number =~ /[^1]1$/ ) { $sufix = 'st'; }
 if ( $number =~ /^2$/ or $number =~ /[^1]2$/ ) { $sufix = 'nd'; }
 if ( $number =~ /^3$/ or $number =~ /[^1]3$/ ) { $sufix = 'rd'; }

 print $number . $sufix, $/;

 }
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and i get 1st, 3rd, 13th, 21st, 22nd, 101st, 112th, 111th I believe this will work for all your cases, i would test it more though. ED: changed a var name, didn't like it after i looked at again