Can you describe it? Was it a game that you played online or downloaded? Some of the popular math resources I can think of:
- Timez Attack: still elementary school age. Download. Paid. Practice times table.
- Evolver: pre-algebra age. Download. Paid. Also an online multiplayer version.
- There is a sequel to Evolver, but I'm not sure if it's supported. I think the company is focusing on online multiplayer (Dimension M).
- Khan's academy. Not really a game, but has gaming elements. Complete units, get streaks, earn badges. Various levels. Free.
- Alcumus (AoPS). Like Khan academy. Problem based with many gaming elements.
- Decartes Cove. Purchase. Myst + Math = Win. Expensive but depending on your child may be a good fit.
Those are the ones that jump to mind. If you can describe the game in more detail maybe something will come mind. Good luck.
JB