Why Publish Homework Solutions?

Ray Ontko
Department of Computer Science
Earlham College

It may seem silly for me to assign homework problems and then also provide fully worked solutions on-line or on reserve in the library.

Here are my reasons for making the solutions so readily available:

I want you to be able to check your own work. If you're working on problem 1, and problems 2, 3, and 4 all require your understanding of number 1 to be correct, I'd like for you to have instant feedback on whether you got the answer right, and whether you considered all the appropriate steps in coming up with your solution.
I'd like for you to be able to see different ways of approaching a problem. My solution or the publisher's solution are often not the ONLY ways of doing the problem. In fact, I often illustrate a different approach than the publisher if I can think of one.
I'd like for you to "see" solutions even if you can't generate them. There are a number of problems in the text that require special insight into a problem that most of us can't generate, but we can appreciate. It's more important to me that you be able to understand the solution and be able to apply it, than it is to be able to generate it. Sophomores can learn relativity, but it took an Einstein to invent it.
Perhaps most importantly, if you can't find the answer without the hint that the solution provides, I WANT YOU TO REPRODUCE THE SOLUTION, IN YOUR OWN WORDS, STEP BY STEP. In doing so, it is my sincere hope that you will pay attention to what you're writing and that you will "get it."

This is what I mean when I say "I see no reason why anyone can't get a perfect score on every homework."

As a practical matter, I suggest that you NOT keep my (or the publisher's) solutions open on the desk (or desktop) while you're working. I suggest that you first struggle with the problem. If you need a hint, read the solution, close it, and go get a drink of water (or whatever). When you come back, if you "got" it, you should be able to work the rest of the problem. If not, repeat the above process (you may have to alternate trips to the water fountain with trips to the bathroom) until you "get it."

If I only wanted to accomplish #1 above, I would only give the answers. A lot of texts do this, or only provide the answers to odd questions. My goal is to use the exercises to make sure that EVERYONE in the class really gets it, really gets what's significant in the chapter. I could just work them in class, but class time is too important for re-working problems.