You are looking at a very old, but free version of the course. If you are interesed the most recent version, check it out on the Perl Maven site.
>perl examples/bc/bc5.pl # You named your test '30'. You shouldn't use numbers for your test names. # Very confusing. ok 1 - 30 ok 2 - 23+7 not ok 3 - 11+1 # Failed test (examples/bc/bc5.pl at line 20) ok 4 - 2*21 1..4 # Looks like you failed 1 tests of 4.
The first entry in the @sets array is not good as the operation will be executed by Perl and not by bc.