Flow Traders publishes its Graduate Trader process step by step, and the online part is a single numerical test of mental math and number sequences. That makes the preparation unusually clear: speed and accuracy on arithmetic, and spotting sequence rules under time pressure.
What Flow Traders does not publish is the format. The counts and marking on this page come from a prep site that Flow Traders itself links from its graduate page, Trading Interview. Linking a site is not an endorsement of its figures, so treat them as a guide and follow your invitation.
After the test come two interviews, one with a recruiter and one with a trader who will ask brainteasers, and then a case study with two senior traders.