Active Games for Math
Sitting still can be hard for kids, but math doesn't have to happen at a desk.
Numberlines
A numberline big enough to walk on can be used for counting, skip counting, adding or subtracting. Here's one we used.
It would be pretty easy to make one with sturdy paper or fabric and a permanent marker. Cut a long strip, one to 2 feet wide and write the numbers on. Just make sure the numbers are far enough apart that a person fits on each one. My kids liked to run along it calling out each number as they stepped on it. Counting by 2s or 3s takes big steps. Or they would stand on a number and someone else would call out directions like "add 2" or "take away 3" and they would travel that many steps.
On a grid
While waiting for carpool, we used to play a game on the tile floor in the apartment courtyard. Each kid stands on a tile square and one person calls out directions like "2 steps forward", "turn left", "one step backwards". If all players start facing the same way they can check each other for help with right and left. And there shouldn't be any collisions. For a more advanced version, they can start facing different directions and the person calling has to think through whether they will collide.
With Dice
If you want some randomness this article has directions for a dice-based active counting game.
Whether it's a formal game like these or just adding counting to some of what your kids are doing anyway, bring some counting into your active play.