Hi mominsac,
Last year our middle school had a math club and kids did both math competitions and Science Competitions. The only one we couldn't participate in was Math Counts because it conflicted with Sci Oly. It is a big one to miss out on. But we did AMC 8, Continental Math, Sigma Math, and Math Olympiad. I was very pleased that my DS10 and DS12 were able to participate.
This year there is no math club. Very disappointing. They offered one math competition (AMC 8) and Sci Oly. I think it is the lack of a teacher-sponsor than any other reason for non-participation.