Kenken puzzles for mental math and logical thinking
Here's another fun idea to get a bit of mental math into the math lessons in early grades... play KenKen puzzles! (And they are really neat logical thinking puzzles for any "grade" or age - I enjoy them too!)
You can play Kenken online here - options include the puzzle size, operations to use, and difficulty level.
The image above shows a 5x5 solved Kenken puzzle that uses all four operations.
You might also check the offer for free weekly KenKen puzzles that Denise mentions.