Visit this website for free math and STEM activities, games, lesson ideas, printables, and more from MIND Research Institute and similar organizations. Most of these resources can be adapted to any grade level in elementary and middle school. Students can explore problem solving with an app called BigSeed and design math games. Teachers can read about the state of STEM in the United States in an infographic, implement game design courses in their classrooms, access math lesson ideas, and find games to use during family STEM nights.
Full Link: https://www.mindresearch.org/stem-resources