Quick drills for times tables, 2-digit addition, and division facts. Each set is five problems on a big on-screen keypad. Pick the seconds per problem, or turn the timer off.
No sign-up and nothing to install. On a phone or tablet, use Add to Home Screen to open the drills full-screen like an app.
Older kids: SHSAT Drills has free 8th-grade SHSAT math practice and full-length practice tests.