Math Chimp is a curated collection of videos, 200 or so games, and printable worksheets that can supplement #math instruction in grades 1 through 8. All resources are aligned with Common Core State Standards.
Sites that I can't do without as a math teacher (and what's so special about each one!) Links to virtual manipulatives, discovery-based lessons, free graphing software, question prompts, eBooks, and more.... Tons of resources for math teachers