The Optiver 80 in 8: how to prepare for the mental maths test

Candidates describe a mix of addition and subtraction, multiplication including decimals, division, fractions and percentages, under a single eight-minute clock. Many report that wrong answers are penalised, which changes how you should treat a question you are unsure of. Details vary by year and role, so treat any single description as approximate.

QuantMax's 80 in 8 reproduces the shape: eighty items in eight minutes, rotating through the same families, the same level for everyone so scores compare on the leaderboard. It counts right answers, so it measures raw pace; practise the penalty discipline with Beat the odds, where a wrong answer costs a third of a point.

Most people sit their first run somewhere between 25 and 40. Scores around 60 are commonly cited as strong. The gap closes with practice faster than people expect, because most of the time lost is not calculation – it is hesitation over which method to use.

• Multiplying near a round number: $48 \times 52 = 50^2 - 2^2 = 2496$. Look for the pair either side of a round base.
• Splitting one factor: $37 \times 6 = 30 \times 6 + 7 \times 6 = 222$, left to right, so the biggest part is done first.
• Halving and doubling: $25 \times 48 = 50 \times 24 = 1200$.
• Percentages as fractions: 12.5% is $1/8$, 37.5% is $3/8$, 16⅔% is $1/6$.
• Knowing the fraction-to-decimal table cold: sevenths, ninths, elevenths, sixteenths.
• Order of magnitude first: decide where the decimal point goes before you work out the digits.

The arithmetic lesson teaches each with worked examples, and every missed item in a drill links back to the technique that would have solved it.

• Do not stall. If a question has not opened up within a few seconds, move on.
• If wrong answers cost points, skip rather than guess on anything you cannot estimate.
• Use estimation to check: a product of two two-digit numbers has three or four digits; a percentage of a number is smaller than the number.
• Warm up for five minutes beforehand – the first minute of a cold test is the slowest.

1. Day one: sit one 80 in 8 cold to get a baseline.
2. Days two to seven: fifteen minutes of drills a day on your two weakest families, then one full run.
3. Days eight to twelve: alternate full runs with drills on whatever you missed most.
4. Days thirteen and fourteen: full runs only, at the time of day you will sit the real test.