Answer:
It really depends on the person
Explanation:
If you made a game that was about ww2 and you played a leader and made choices that might work but then you not learning the real history because your making your own choices. For math I would think that if you played a game that required a lot of math like an Engineering game that could work. I know you didn't ask this in you question but for learning a language I have a lot of friends that change the language of a game to the language there learning so if there playing a game like Minecraft the could learn when there playing.