Investigation Math Words and Ideas
Investigation Games
Investigation Math Tools
Math Playground
Coolmath4kids
Figure This!
Math-a-rama
Kids' Place Mathematics
KenKen Math Puzzles
2048
Solve Me Mobiles
Solve Me Puzzles
The Factor Game
The Product Game
Kakooma
https://nrich.maths.org/primary
https://www.coolmathgames.com/
Khan Academy
GregTangMath.com
Math Glossary/Harcourt
mathsisfun/dictionary