Try all features free for 24 hours from registration, with unlimited use and no credits consumed. No card required. After the trial, keep 10 free uses per solver, 10 memory rounds and 10 random new questions per practice type with explanations. Allowances do not reset daily. Existing trials are honoured. Guides are free to read without signing in.
US$14.99 / 7 days
A one-time US$14.99 payment unlocks all features for 7 days from payment confirmation. Unused trial time is not added. No automatic renewal.
Member mock exams: 6-minute Switch, 5-minute Digit and 9-minute Grid presets, fullscreen focus, saved history and per-question scores and timing.
Grid dual-task and PEAK familiarization samples; non-members can preview the exam and reports.
Sequence memory: dot recall with 3, 5 or 7 positions; not a complete dual-task Grid simulation.
Pipeline logic: position permutations, intermediate steps and unknown-box solving.
Figure reasoning: six transformation families on a 3×3 grid and candidate-rule checks.
Numerical reasoning: equation blanks, distinct-digit constraints and valid-solution checks.
Data interpretation practice: growth, shares, ratios and unit conversion.
Difficulty-based practice, answer history and wrong-answer retries, in Chinese and English.
Sign-in is required to solve questions and save practice history. Accounts with active paid access cannot buy again. Available payment methods are shown at Stripe checkout.