Two tracks: Grade 7 (ten steps, one skill each, built from the released SOL test) and Quadratics (four steps, from the vocabulary sheet). Every step has the same five parts, in order:
The idea — read it together. It is short on purpose.
Watch one — tap Next line to reveal the working one line at a time. Ask Yiyang what comes next before each tap.
Your turn — Yiyang says the answer out loud first, then taps it. The page says why, right or wrong, and the answer is always one tap away.
One more — fresh numbers every tap. Keep going until it feels easy.
Sure or not sure — Yiyang decides. The dot next to the step remembers it (on this device only).
Nothing is scored, ever. Next class, start at the first step without a green dot.