Free online math flash cards that I made

Got a phone, computer, or tablet? You can practice doing math in your head! 
As a parent of young children, I observed their tablet time throughout the week. I mean, which kid doesn’t love their tablets? Lately, I’ve introduced them to the idea that tablets are more than just devices to watch baseball highlights, cat videos, and games. It was also a key to unlock the world’s knowledge all in the palm of their hands. So since I have a background in writing code, I made a procedurally generated math quiz… basically, online math flashcards that get harder and harder as the player progresses and level up.