Oh, and to concur with the "calculator barely needed" crowd from calculus
-in general, in my class, when I go over problems, I just get to the point where I say "the rest is just simple algebra and arithmetic; according to the answer in the back of the book, it works out to 2.3784" I generally don't have my class bother with the trivial stuff - we just agree that if everything agrees at whatever step we make it to, then any errors after that point fall into the "stupid mistakes" types of errors. I also don't take off credit for really stupid arithmetic mistakes... the trade off is that I expect them to do more arithmetic in their heads rather than with the calculator. It's amazing at how much progress they make in one semester; I often have students who have become so calculator dependent that they can't add simple 2 digit numbers in their heads without grabbing their trusty TI.