I loved this idea, but for my first try, I decided to create the problems myself. My students and are working on one-variable inequalities. My largest class has 16 students, so I created 16 problems on index cards and the solutions to each one on separate index cards.
To start, I gave each student one problem index card and one solution index card. The students needed to make sure they could do the given problem. Once they were set, I took back the solution index card and they were off. Students were to trade problems with another student and if any questions or problems arise, students are to ask the person they got the problem from.
For some reason this year, I have students who still ask me first. No worries, I gently remind them that the student who previously had the problem will help them. AND, I'm still having trouble with students who WILL NOT TALK. That's why they ask me first, because they won't talk to each other....yet. I will break them.
Here's why I like this activity:
Students know that as they are doing a problem they have to understand it well enough to teach someone else and that takes their learning to a whole new level.
I've done an activity like this in the past, but the students didn't exchange problems, this activity is better because they get to become experts on so many more problems.
Next time I will have the students create the problem as suggest by @LizCrabtree. I think seeing a problem as it's created will add another dimension to their learning.