Optiver 80 in 8: the mental math test, free
The "80 in 8" is Optiver's famous numerical screen — 80 multiple-choice questions in 8 minutes, no calculator, with a −1 penalty for every wrong answer and no skipping. Take the full run below in the exact format, get a score, and see what to drill next. No signup.
Maintained by Stanley on the QuantVault team · format last verified June 2026 against candidate reports and public clones. How we keep this accurate.
What the 80 in 8 actually is
The 80 in 8 is the mental-arithmetic gate at the front of Optiver's process for trading and research roles. It is deliberately brutal: 80 questions, 8 minutes, which is about six seconds per question if you want to finish. There is no calculator, and a wrong answer is not just a miss — it costs you a point, so guessing is actively punished.
It is a separate assessment from Optiver's other modules. The online battery (Number Logic, the probability round, and the Zap-N cognitive games) tests pattern-finding and reaction; the 80 in 8 tests raw, accurate arithmetic under a clock. Strong candidates clear all of them — this page is for the arithmetic one.
The exact format
373 + 57 = ?) and missing-operand (66 × ? = 138.6). The second shape trips people up.How to prepare
- Drill the times tables to 19 and the common fraction–decimal conversions. Knowing
1/8 = 0.125,3/8 = 0.375,1/6 ≈ 0.167on sight saves seconds every time they appear. - Practise the missing-operand shape on purpose.
66 × ? = 138.6is a division in disguise (138.6 / 66 = 2.1). Reframing it instantly is a trained reflex, not a talent. - Respect the −1. When two options are close and you are unsure, a fast sanity estimate beats a coin-flip — a wrong answer is a two-point swing against a skip you can't take, so don't answer on noise.
- Run the full eight minutes, not just bursts. Stamina and pacing are half the test; the speed-up curve only stops feeling violent once you've sat the whole clock a few times.
When the arithmetic is solid, build out the rest of your Optiver prep — the modules below are where most of the assessment's weight actually sits.
How we keep this accurate
The format here is cross-checked against public candidate reports, the well-known practice clones, and our own harvested Optiver assessment corpus. Every question is generated and its correct option computed in code, then checked by an automated harness over hundreds of thousands of cases, so the answer marked correct always is. If you've sat a recent 80 in 8 and something here is off, tell us at [email protected].