A number appears as a word (forty-seven) or a digit (47) — quickly select the matching form. Tests the speed of your numerical transcoding system, which maps between written digit and spoken/written word forms. Based on McCloskey (1992).
Very Easy
Numbers 1–10, 16 trials, 4s limit — word → digit only
Easy
Numbers 1–20, 20 trials, 3s limit — both directions
Medium
Numbers 1–99, 24 trials, 2.5s limit — both directions
Hard
Numbers 1–99, 28 trials, 2s limit — both directions
Expert
Numbers 1–999, 32 trials, 1.5s limit — both directions
Scientific Background
Based on: Number Transcoding / Numerical Lexicon Mapping (McCloskey, 1992) (McCloskey & undefined, 1992)