Our first speaker of the semester, Roberto Bosch Cabrera, has generously provided us with a set of problems and solutions. The concepts behind these problems should be very helpful to our students preparing for the next set of AMC contests. In addition, the art of writing excellent articulations like Roberto’s is critical to advancement in mathematics and is applicable to a variety of other fields.
Here are the first two problems and the solutions which you will find in the attached Adobe Acrobat File (pdf).
Metroplex Math Circle 
Hello,
I am a math coach for Harmony andI truly appreciate you posting the problems with solutions. I was working on these problems with my students when we realized that Problem 1 is missing a case where x =-1, y=-1, z=1.
Thanks again for posting these problems. We truly enjoyed them.