Really nice. I see you have put a lot of effort into this game.
I just have a few suggestions:
1. Reduce the difficulty of the maths, because obviously, some people haven't learnt those kinds of mathematics. Reduce the math to only addition, subtraction, multiplication, and division. Maybe you can go a bit further but just reduce the difficulty.
It's also going to get boring when the player is actually stuck on the problem or what to do so yeah.
2. The font and the background. They don't fit with each other. I dunno if it's just me or not, but stuff such as the yellow font on the blue background hurts the eyes, the white font on black background hurts the eyes as well. So i recommend changing some of them.