Every test below runs on the same engine: pick your level and mode, answer with clicks or the 1–4 keys, and finish with a full mistake analysis showing exactly what to review. Progress and badges are saved in your browser — no account needed. Each test has four modes: Practice (instant feedback with explanations), Exam (score at the end), a 60-second Speed Challenge, and a Daily Challenge that serves the same questions to every visitor each day, so you can compare scores with friends.