Zetamac & Adaptive: type the answer (auto-advances when right). 80 in 8: Optiver-style multiple choice — +1 right, −1 wrong, skip is free. Every question is tagged, so your accuracy and speed by category (×11, ×12, ÷12, fractions, …) build up below; Adaptive then weights toward your weak +−×÷ spots, and the chart tracks your progress.