Recently i've been trying to find an app like Duolingo but for math. Essentially, a way to practice bite sized pieces of mathematics to keep proficiency up. Un

Recently i've been trying to find an app like Duolingo but for math. Essentially, a way to practice bite sized pieces of mathematics to keep proficiency up. Unfortunately the current selection of apps are fairly low quality and only allow very basic arithmetic. Any suggestions? May just build it myself otherwise.