Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Two subjects: reliability and usefulness for PE Exam

First issue:Check some examples from the manual first (say, conversion of coordinates polar<>rectangular). It did not work for me. See if it works for you.As for calculator overall, nothing special. Just run of the mill calculator with too many things piled up on the keys.Second issue:As for PE exam (where it is, for some reason, one of the two calculators in the list), a calculator lighter on features is more than sufficient, and you will not waste precious studying time to learn the quirks of a calculator.