Speed arithmetic tests at trading firms

Apply to a trading or market-making firm and one of the first things you may be sent is a quick-fire maths test: lots of short calculations, a few minutes on the clock and no calculator. It checks whether you stay fast and accurate under pressure, a skill trading firms clearly care about.

The first attempt often feels brutal. That's normal. Arithmetic speed comes from a small set of habits practised little and often, not from being a maths prodigy.

The formats candidates report

Trading firms rarely describe these tests on their own websites, so most of what is known comes from candidates and prep sites. Exact numbers differ between sources and change from year to year.

Some patterns are consistent across sources:

• Reported: The questions use whole numbers, decimals, fractions, percentages, and two-digit multiplication and division
• Reported: Marking is often +1 for a right answer, −1 for a wrong one and 0 for a skip, sometimes with no way to go back to earlier questions
• Reported: Online assessments at trading firms often arrive within about 48 to 72 hours of applying, so it pays to practise before you apply, not after the invite lands
• Unverified: One guide says Optiver allows a retake only once every 8 months, so your first attempt may really count
• Unverified: Pass marks quoted online vary between sources and firms don't publish them, so we don't repeat them

Not every firm uses a timed arithmetic screen. Official: Jane Street's trading interviews page describes interviews built around problem solving and probability, says you don't need finance knowledge, and offers a mock interview video. Unverified: Some online guides claim it sets a mental maths test, which its own page doesn't mention.

What the questions look like

These examples are original and written for practice. The last column shows a faster route than working it out in full.

Negative marking changes the maths

If a right answer scores +1, a wrong answer −1 and a blank 0, then a guess only helps when you're more likely to be right than wrong. Your expected score from answering is your chance of being right minus your chance of being wrong. At 50% sure, that's zero. Below 50%, you lose marks on average.

That makes accuracy just as important as speed:

How to use this in the test:

• Skip quickly: if a question will clearly take far longer than the rest, skip it straight away rather than stalling and then skipping
• Decide once: if there's no going back, commit to answering or skipping and move on
• Answer only when you're more likely right than wrong, because a wild guess at a typed answer almost never pays
• Check the rules: not every test uses negative marking, and if blanks and wrong answers both score zero, answer everything
• Practise typing numbers, because fumbling decimals, fractions and minus signs costs real time in typed-answer formats

Techniques worth learning

• Round and adjust: 99 × 7 = 700 − 7 = 693
• Split the number: 38 × 12 = 380 + 76 = 456
• Multiply by 25: multiply by 100, then divide by 4, so 64 × 25 = 6,400 ÷ 4 = 1,600
• Divide by 5: double it, then divide by 10, so 340 ÷ 5 = 680 ÷ 10 = 68
• Swap percentages: 8% of 50 is the same as 50% of 8, which is 4
• Scale decimals away: 7.2 ÷ 0.08 becomes 720 ÷ 8 = 90
• Know common fractions as decimals: 1/8 = 0.125, 3/8 = 0.375, 1/6 ≈ 0.167, 1/7 ≈ 0.143, 1/9 ≈ 0.111 and 1/11 ≈ 0.091
• Make the basics automatic: times tables up to 12 × 12 and squares up to 20 × 20 should come without thinking

A practice plan

Before paying for any practice, check your careers service. Official: Many universities give students free access to practice platforms, including Cambridge, Warwick, Bath and Loughborough. Formats vary, so check what yours covers.

1. Accuracy first. Start at a relaxed pace until you're getting nearly everything right.
2. Add the clock. Switch to the format from your invite, or a common one such as 80 in 8 if you haven't applied yet.
3. Keep a simple log. Note your score and the type of every mistake: a slip, a misread, a sign error or a slow question type.
4. Drill your slowest type on its own. For many people it's fractions or division by decimals.
5. Little and often. Ten focused minutes a day tends to beat an hour once a week.
6. Do a full dress rehearsal. Once or twice before the live test, practise in the same conditions: quiet room, same device, no calculator.

Reported: If early scores feel impossible, you're in good company. Students have described exactly this on finance forums, and the fix is steady practice rather than a secret trick. Be wary of anything sold as a firm's test questions or answers.

Beyond the arithmetic screen

Reported: Later rounds at many trading firms focus on probability, expected value and live betting or market-making games with an interviewer, where your reasoning and risk discipline matter more than getting the biggest number. Some firms also use game-based cognitive assessments before interviews.

If you're applying to banks as well, their numerical tests are a different skill: reading tables and charts, usually with a calculator. The numerical reasoning guide covers that, and the 72-hour plan helps when an invite lands.