Here's a fun math game that both my first grader and pre-k students can play together. It is from KidsCount123 I've used a few games from this site and I really like them. Today we played a version of yahtzee. It is called kindergarten yahtzee but like I said it worked fine with my first grader and pre-k student. Take turns rolling 2 dice. Add the numbers and color each rectangle as you go. The player who has all the numbers colored first wins. It gets hard at the end. And my kids' attention span was starting to wane. So we decided to role 4 dice but still only add two of them. That made the game end a lot faster.
We also played "Bump" This is another fun addition game. My kids enjoyed "bumping" each others' game pieces off the board.