HI all, I am working my way slowly through some classical mechanics books, and I don't think I could function without my CAS (most often my trusty HP 50g, sometimes Giac/Xcas). I have never been very good at pages of algebra, often dropping negatives or whatever, bad enough that working through Physics problems over and over again was just too painful. Now with a CAS I can double check my work, solve for t without dropping an exponent, etc etc. However, I feel guilty. Should I worry that I am missing out on something? If I sit for the FE test someday will I regret leaning on the CAS? Other thoughts? It isn't that I don't know how to do algebra, I am just too inconsistent to keep it together without a type if there more than half a dozen lines. Also -- I follow Morin's advice and don't look at the answer unless I have to and have taken 24 hour cooling off period; usually I am able to find my own mistakes by cross checking now that it doesn't take hours to rewrite pages of equations trying to find a dropped negative. For context, I am an autodidact in my forties, with a B.A. in math (liked proofs but not lab or lots of applied algebra). I work as a data analyst / computer programmer. Right now I am working through Morin's Problems book, and hope to switch to the big red book once I get some basic AP Physics skills. Thanks for reading, looking forward to hearing anyone's thoughts.