I'll raise you the work to arrive at the solutions, as well. At least, in my school answers were a small, nearly insignificant portion of the credit for a probl

I'll raise you the work to arrive at the solutions, as well. At least, in my school answers were a small, nearly insignificant portion of the credit for a problem - no work meant almost no credit, which is critical for engineers. (That way if you make a mistake you can debug it!) I'd imagine all of it has to be available in order to even post the exercises, but editing/formatting the work and solutions almost certainly is quite a lot of work. Edit: In retrospect, in this context the work is the answer, so my distinction may be irrelevant. (I'll leave the comment as a hearty agreement with the parent though - solutions often help solidify ideas for me, and are great references later when applying the ideas in the real world!)