Dude, hell yeah! I was just shopping for this exact thing not that long ago [1]. I've never been great with math and wanted something I could practice with away from my laptop. Love that it works in the browser, too. Well done, this is really nice.
One small piece of feedback: on my Pixel, the Android keyboard obscures the green button. So when I'm answering a numerical question, I use your number pad to enter the digits, and then use the enter key on my Android keyboard. This feels weird, but I guess with regular use it wouldn't.
[1] https://graybearding.bearblog.dev/how-im-teaching-myself-mat...
One small piece of feedback: on my Pixel, the Android keyboard obscures the green button. So when I'm answering a numerical question, I use your number pad to enter the digits, and then use the enter key on my Android keyboard. This feels weird, but I guess with regular use it wouldn't.