Answer Key's to Worksheets

I believe that students do need to practice a skill in order to get good at something. This often translates into lots of questions and problems and opportunities for students to practice. Typically, for my math and physics classes, this takes the form of worksheets or practice problems out of the book. 

One thing I try to make sure I have for my worksheets or assignments however is some way for the students to know if they are getting it right. 

For my algebra assignments out of the book -- I remind my students that math textbooks almost always have an answer section in the back, and I tell them to check their work as they go. (One thing I have not done that just came to mind is model to them what that looks like in practice, and how to deal with mistakes...) For assignments that do not have answers, I have been known to write all the answers on the board, or on the bottom of a worksheet, but in random order. This way the students have to come up with an answer, but if they see that answer on the board then they have some confidence that they did it right. To avoid process of elimination at the end, I usually throw a few more answers up than I assigned.

My physics assignments typically come from several sources -- a hardcopy textbook, made up questions on worksheets, or several handouts of supplementary practice problems. Most of these do not have a ready made answer sheet, or have multiple parts that should be checked along the way before arriving at the "final answer". For many of these assignments, I provide the answers in a multiple choice format:

      m = {1.20,     1.47,      1.93,       2.31,     2.88,    3.06} kg

One of the six options listed is the correct mass, and the other 5 are just random distractors. The idea came to me when one of the students complained to me "Can you just give us the answers?".  At first I thought, "Of course not!" but then I remembered my assignments at MSU where we had to enter our answers in online, and they would tell us if we were right or not. I remember being frustrated at these assignments, but in a good way because I kept returning to the problem and trying to figure out what was wrong until finally I found an answer that worked. I haven't taken the time to find a way to do that with my assignments yet, but having the answers available for students is a step in that direction perhaps.  

To help me come up with such answers, I set up an excel file that I can enter the correct answer in one cell, and it will come up with six answers that are all reasonably close in size compared to that answer.  The correct answer is randomly placed somewhere in those numbers:

If you want to try it for yourself, you may download it here.  To adjust where the answers round to, select the options and push the rounding button in the number tab above, highlighted in yellow above. 

To create a worksheet for the students then, I typically have this file open and copy and paste the answers in.  One thing I have found necessary is to "Special Paste" them in -- by pressing Alt E, S and paste them as unformatted text instead of cells from a spreadsheet. That way the formatting looks good, and the numbers in the worksheet are fixed instead of linked to the constantly changing excel file.