OA Prep
Every online assessment game, explained.
Trading, banking and consulting applications now screen you with timed tests before anyone reads your CV. This page explains what each of the 14 games here measures, where the format turns up and how to actually train for it. All of it is free.
New to this? Start here.
If you have never sat an online assessment, this is the whole thing in three paragraphs.
Where it sits
The OA lands within days of your application and is usually marked automatically. Clear it and you get an interview. Miss the bar and nobody reads the rest.
What it measures
Arithmetic speed, pattern spotting, working memory, reaction and how you behave when the questions get hard. Very little of it is A-Level content and almost none is finance knowledge.
Why practice works
The formats repeat year on year. The gap between a cold first attempt and a tenth attempt is large, and it is the cheapest advantage available to a first year.
Speed and numeracy
The maths round. Almost every quant and trading process opens with one of these, and a lot of banking numerical tests are a slower version of the same thing. This is the group to start with, because it is the one where practice moves your score the most.
Mental Maths
Addition, subtraction, multiplication and division, one question at a time. Type the answer and the next question appears instantly. Choose 30s, 60s, 120s or 300s; the 120 second game with all four operations is the ranked one.
- What it tests
- Raw arithmetic throughput. Your score is how many you clear, not a percentage, so hesitation is the thing that costs you.
- Where you will meet it
- The opening test at most prop and market making firms (Optiver, Flow Traders, IMC and similar), and a fair proxy for the numerical reasoning tests banks use.
- How to get better
- Nothing is deducted for a wrong keystroke, the question only clears when the answer is right, so type immediately and correct as you go. Learn times tables to 20 and get comfortable dividing by 7, 11 and 13.
Fast Fractions
A fraction appears, you type the decimal. Answers are checked to three decimal places, so 7/16 is 0.4375 and 3/8 is 0.375.
- What it tests
- Recall rather than calculation. Trading tests assume you already know these and are timing something else.
- Where you will meet it
- Inside mental maths rounds, and in market making questions where prices move in halves, quarters, eighths and sixteenths.
- How to get better
- Memorise the conversions from halves through twentieths. Anything with 8, 16, 32 or 64 underneath should be instant, not worked out.
Sequences
A run of terms appears and you type the next one. Questions come from a verified bank and include fractions and powers, not only arithmetic steps.
- What it tests
- Pattern recognition under time pressure, plus the discipline to abandon a wrong idea quickly rather than forcing it.
- Where you will meet it
- Sequence rounds in trading assessments, including the Optiver, Flow Traders and Maven style tests, and the numerical sections of graduate aptitude tests.
- How to get better
- Work through it in a fixed order: first differences, then second differences, then ratios, then two interleaved sequences. If nothing lands in a few seconds, skip and take the next one.
Daily Challenge
Eight sequences, easiest first, once a day. Up to 30 minutes with the clock as the tiebreaker, a daily board, a shareable result and a streak that resets if you miss a day. New challenge at midnight UTC.
- What it tests
- Consistency more than ability. It exists so that prep is a habit instead of a panic the night before a deadline.
- Where you will meet it
- Not a test format in itself. It is the daily rep that makes the rest of this page work, and the easiest way to compare yourself with people on your course.
- How to get better
- Do it at the same time every day. Ten minutes a day for a term beats a weekend of cramming the week applications open.
Markets and estimation
The judgement games. These are the closest thing on the site to what a trader actually does: price something with incomplete information, decide whether the price on offer is wrong, and be willing to do nothing when it is not.
Dice Markets
Some dice are face up, some hidden. A dealer quotes a bid and an ask on the total. You buy if the ask is too low, sell if the bid is too high, and pass if the quote is fair. Difficulty presets change how many dice are hidden, how tight the quotes are and how long you get per round.
- What it tests
- Expected value under uncertainty, and the discipline to pass. Trading firms care as much about whether you trade a fair market as whether you spot a bad one.
- Where you will meet it
- Market making rounds and trading games at prop firms, and the on-the-spot pricing questions in trading interviews.
- How to get better
- A hidden die is worth 3.5. Add the visible faces, add 3.5 for each hidden one, then compare with the quote. Passing on a fair market is a correct answer, not a wasted round.
Card Markets
A dealer quotes a bid and an ask on the sum of five cards, some face down. Unlike dice, cards are drawn without replacement, so what has already been revealed changes what the hidden cards are worth.
- What it tests
- Expected value with conditional information, and updating a price when new information arrives mid round.
- Where you will meet it
- Card based trading games in prop firm assessments and superday market making exercises.
- How to get better
- Look at what is already showing before you price the rest. If the visible cards are high, the unseen ones are worth less than the deck average, and the fair value moves with them.
Fermi Estimation
Eight questions, 45 seconds each by default. For each one you give a low and a high that you are 90% sure contains the answer. Capturing the true value scores, and the tighter the interval the more it scores. Miss it and the question is worth nothing.
- What it tests
- Structured estimation and calibration: whether you actually know how much you know.
- Where you will meet it
- Consulting case maths, trading interview brainteasers and the estimation questions Optiver style firms use to see how you reason out loud.
- How to get better
- Break the question into factors you can each get within a factor of three, then multiply. Keep intervals honest: tight when you know the answer, wide when you are guessing. Hedging everything scores badly.
Cognitive and reaction tests
The gamified assessments. Banks and trading firms increasingly screen with short psychometric games rather than a maths paper, often through providers like Arctic Shores. You cannot revise for these the way you revise for maths, but the formats are unfamiliar the first time and familiar the tenth, and that alone is worth several points.
Arrow Game
60 seconds of arrows. Answer the direction of the centre arrow while ignoring the ones either side of it, and give the opposite answer when the arrows are red. Correct answers score +1, wrong answers score -1.
- What it tests
- Response conflict and inhibition: whether you can follow a rule that fights your first instinct, and how fast you recover after a mistake.
- Where you will meet it
- Arctic Shores style gamified assessments used across banking and trading, where a flanker task is close to standard.
- How to get better
- Wrong answers subtract, so accuracy beats speed here. Say the rule to yourself on red rounds, and reset immediately after an error instead of chasing the lost point.
Reaction Time
The screen turns green after an unpredictable delay and you click as fast as you can. Five rounds, averaged. Clicking early restarts the round, so there is no gaming the wait.
- What it tests
- Simple reaction speed, the baseline every timed game is layered on top of.
- Where you will meet it
- Reflex sections of gamified assessments and trading aptitude screens, and as a warm up before anything timed.
- How to get better
- Somewhere around 200 to 280ms is a normal adult range. Rest your finger on the button, watch the whole screen rather than one point, and do not try to predict the delay.
Memory Digits
Digits flash one at a time, then you type the sequence. It starts at three digits and adds one every time you get it right.
- What it tests
- Working memory, specifically digit span: how much you can hold while something else demands attention.
- Where you will meet it
- Cognitive sections of trading firm assessments, and indirectly in any numerical test where you have to carry figures between screens.
- How to get better
- Chunk the digits in groups of three and rehearse them out loud. Most people plateau around seven to nine digits, and chunking is what gets you past it.
Sequence Memory
Squares light up one after another and you click them back in the same order. Every level adds one more step.
- What it tests
- Sequential and spatial working memory, and attention across a longer stimulus.
- Where you will meet it
- Gamified assessment batteries of the Arctic Shores and Pymetrics type, and cognitive screens at trading firms.
- How to get better
- Store the pattern as a shape or a route across the grid rather than a list of positions. Shapes survive in memory far better than lists.
Visual Memory
A set of tiles flashes for just over a second, then you click every one of them. Get it right and the grid grows; you have three lives.
- What it tests
- Spatial recall of information presented all at once, which is a different skill from remembering a sequence.
- Where you will meet it
- Memory sections of gamified assessments, and the pattern recall parts of graduate aptitude batteries.
- How to get better
- Take the whole grid in with one soft focus instead of scanning tile by tile. Scanning uses the time you need for encoding.
Chimp Test
Numbers are scattered across a grid and vanish once you click the first one. You click the rest in ascending order from memory. Each round adds a number, and three strikes ends the run.
- What it tests
- Fast encoding of position and value together, under a very short exposure.
- Where you will meet it
- Working memory sections of cognitive assessments, and it is the single best warm up for the memory games above.
- How to get better
- Lock in the first four positions before you go hunting for the rest. Getting past nine or ten reliably already puts you ahead of most first attempts.
After the OA: interview technicals
Passing the OA gets you an interview, and the interview tests something completely different. Worth starting early, because unlike the games this one is pure knowledge and cannot be crammed in a week.
Practice Questions
Multiple choice questions across accounting, valuation, M&A, markets, brainteasers and commercial awareness, with an explanation after every answer and a readiness score per topic.
- What it tests
- Technical knowledge and recall, not speed.
- Where you will meet it
- First round and assessment centre interviews, plus the written technical tests some banking and PE processes run.
- How to get better
- Ten questions a day in whichever topic shows red. The readiness bars are there so you stop practising what you are already good at.
A four week plan for first years.
Doing everything at once is how people burn out in week two. Add one group at a time, in this order.
- Week 1
Build the arithmetic base
Ten minutes of Mental Maths a day, plus a couple of minutes of Fast Fractions. Do not touch anything else yet. Numeracy is the bottleneck for most people and it improves fastest.
- Week 2
Add patterns
Keep the daily maths and add Sequences, then start the Daily Challenge and do not break the streak. By the end of the week you should recognise the common families of pattern without thinking.
- Week 3
Add markets and estimation
Dice Markets on easy, then medium once passing on fair quotes feels natural. Card Markets after that, and a Fermi set twice in the week. This is the part that shows up again in interviews.
- Week 4
Add the gamified tests
One run each of Arrow Game, Reaction Time and the three memory tests at the start of a session, then back to maths. The aim is familiarity with the formats, not a high score.
- Ongoing
Keep the streak, then apply early
The Daily Challenge keeps everything warm year round. Set alerts on the internship tracker so you sit your first real OA with months of reps behind you rather than days.
Questions, answered.
Pick one game and start today.
The Daily Challenge takes ten minutes. When applications open, the tracker tells you which deadlines are live so you are not finding out from a group chat.