We have seen nice improvement in Explore test scores for DS10 for the last three years. Now at grade 5, DS thought Explore was too easy for him and wanted to try ACT/SAT. NUMATS only takes 6th graders or higher, the only option is register directly through the testing agency and choose local high school. Since DS has been working with 8th graders in math class, I don't think a room filled with high schoolers would be a problem. DS might need some basic test taking strategies and get used to the pace and time management.