A full numerical reasoning test in the most common format: 18 questions in 25 minutes, about 83 seconds each, with an on-screen calculator. Each question uses one or two of the exhibits, and you can move back and forth and flag questions to return to.
Treat it like the real thing: one sitting, no notes beyond scrap paper. Afterward, check the pacing panel. If you reached question 10 well after the halfway mark, the fix is to skip and flag sooner, not to calculate faster.