If you are looking for a collection of games rather than a single title, several repositories aggregate math games. These are excellent resources for teachers and parents.
: The viral sliding-tile puzzle. While there are many versions, the original gabrielecirulli.github.io/2048 math games github io top
You might open these games and think, "Wow, this looks like it was made in 1998." There are no particle effects. The fonts are usually system defaults (Helvetica or Arial). The colors are high-contrast (black and white or a single neon highlight). If you are looking for a collection of