I love the idea of using these tennis ball containers for learning games or independent games.
The road to success is not a straight one
definitely addresses the Standard for Mathematical Practice about critiquing arguments of others
Freebie; "I can statements" for each of the 8 Math Practice Standards. Use these during math discussions and lesson wrap-ups. Post them in your room for students to refer to. There is also a small copy for students to glue into math journals.
Lots of great anchor charts here!