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Interview practice

Flow Traders-style 80-in-8 mental math practice

A liquidity provider specialising in ETFs, with offices in Amsterdam, New York, Cluj, Hong Kong and Singapore.

A timed numerical test early in the process is widely reported, in the same speed-arithmetic family as Optiver's.

What this assessment looks like

A speed-arithmetic screen: on the order of 80 questions in 8 minutes, so roughly six seconds per answer. Addition, subtraction, multiplication, division, fractions, decimals and percentages, often with negative marking - a wrong answer costs more than a skip.

  • Two-digit multiplication and division without writing anything down
  • Fraction and decimal conversion at a glance
  • Percentage moves in both directions (a 20% drop needs +25% to recover)
  • Knowing when to skip: negative marking punishes guessing

Train it here

  • Arithmetic Drill - 2.5 timed minutes of exactly this question mix, with a ghost of your best past run to race.
  • Dino Dash - Endless mental-math runner - one mistake ends the run, and the questions climb through ten difficulty tiers.
  • Sequence Sprint - Pattern recognition under the same per-question time pressure.

Also reported at Flow Traders

Number sequences · Probability & estimation · Market making

Hiring now: current Flow Traders quant openings, refreshed daily.

Outcry is not affiliated with Flow Traders and has no access to their assessment content. This page describes formats candidates publicly report, and the drills here train the underlying skills - they are not the firm’s questions.