When I downloaded this, I was like "Oh no, MATH... this is going to be awful." It turned out not to be bad at all though! Fun, cute little game.
I really like how you're able to move a short distance after picking up a number, but then you get locked in place for a bit as you add the numbers. There's a real panic when you realize you're locked in and an eraser is coming for you! I think this mechanic of being forced to hold still only after a few seconds have passed is a really interesting one, I'd love to see it expanded upon. Gives you a lot more room for strategy and fun risk-taking than an immediate lock would.
I will note that I also got the bug where the tutorial text did not display correctly. Luckily I was able to figure it out on my own, since the mechanics aren't super complex or anything.