Quant Mental Math Test: Free 80 in 8 Practice for Trading Interviews

Several trading firms screen applicants for trading roles with a timed arithmetic test before any interview. The questions are not hard one at a time: adding, subtracting, multiplying and dividing integers, decimals, simple fractions and percentages. The clock is the hard part. Eighty questions in eight minutes is six seconds a question, and a wrong answer costs marks.

Candidates report them at Optiver and Akuna in the 80 in 8 format, at Flow Traders as speed arithmetic on the four operations, and at Five Rings as timed arithmetic and estimation. Jane Street asks mental arithmetic inside its phone interviews rather than in a separate test. Nearly all of these reports come from trader candidates.

No firm publishes the format of its arithmetic test. The 80 questions in 8 minutes format comes from candidates: seven Glassdoor reviews of Optiver trader interviews dated 2011 to 2017, two later mentions on Reddit (the newer one about two years old), and an Akuna trading candidate who posted the same format in May 2023. One review has a wrong answer costing one mark and another has it costing two. Optiver’s Sydney campus FAQ says calculators are not permitted in its assessment, and its Europe FAQ says an assessment can be taken once every eight months.

Optiver may no longer send this test first. Five candidates listed the assessment modules they were sent between July 2025 and February 2026. Between them they name probability, sequence and game modules, and none names an arithmetic test. Optiver has not said the test is gone, and a November 2026 candidate describes two one-hour market-making games with many small mental sums in them.

Nobody outside the firms knows the pass marks, so this page does not give one.

Practice in short daily sessions: one timed test, or a few two-minute drills. Keep the penalty switched on. Practicing without a penalty teaches guessing, and the test takes marks off for it. After a test, read the breakdown by operation and the missed questions, then use the free drill on whatever was slowest. The free drill works the way Zetamac does, with typed answers against a clock of one, two or five minutes, and you choose the operations and the kinds of number.

• Round and correct. 94 × 48 is 94 × 50 less 94 × 2: 4,700 − 188 = 4,512.
• Use quarters. 47 × 75 is three quarters of 4,700: 3,525.
• Move to a round percentage. 19% of 270 is 20% (54) less 1% (2.7): 51.3. And 12% of 47 is 47% of 12, so pick whichever is easier.
• Go decimal with friendly denominators. 2/5 + 11/4 is 0.4 + 2.75 = 3.15. Learn the sevenths: 0.143, 0.286, 0.429.
• Check the last digit and the size. The last digit of 94 × 48 is the last digit of 4 × 8, a 2, and the answer is about 4,500. With four options on screen that often leaves one.

With four options and one mark off for a wrong answer, a blind guess wins a mark one time in four and loses a mark three times in four, so on average it loses half a mark. A guess between two options is worth nothing on average. At two marks off, a blind guess loses a mark and a quarter on average. A skip always scores zero.