Oct 08, 2026 by Offer

Optiver 'Make 24' Interview Game 2027: Rules & Strategy

The Optiver make 24 mental math strategy: scan for factor pairs of 24 (1x24, 2x12, 3x8, 4x6), then work backward to build those factors from the four numbers. Always work target-first, never try operations randomly. Narrate your search aloud throughout. Commonly reported by candidates.

What This Question Assesses

Make-24 tests mental arithmetic speed, pattern recognition, and composure under observation — the raw materials of a trader. The interviewer is not just checking whether you reach 24; they are watching how you search. Do you try operations randomly, or do you work from the target backward? Systematic target-first thinking is what separates strong candidates, and it mirrors how traders decompose pricing problems.

Optiver Make 24 Mental Math: How to Answer

Step 1 — List the factor pairs. "24 = 1×24, 2×12, 3×8, 4×6 — plus sums and differences like 20+4 or 30−6. I will aim to build one of these."
Step 2 — Scan the numbers for a pair. Look at the four numbers and ask: can two of them make 12, 8, 6, or 4? Can the other two make the matching factor? Try the most promising pair first.
Step 3 — Work a concrete example. "Given 3, 4, 5, 6: I see 4×6 = 24 directly — so the 3 and 5 must combine to 1: 5−3 = 1, then (5−3)×4×6... wait, that uses all four: (5−3) = 1, 1×4×6 = 24. Done."
Step 4 — Have fallback patterns. If factors fail, try sums (two pairs summing to parts of 24), differences, or fractions: "a/b constructions like (8/(3−8/3)) are rare in interviews, so prioritise integer factorisations."

An example line to narrate: "I am looking at factor pairs of 24 — I see a 3 and an 8 in the numbers, that is promising; can the other two make 1? Yes, by subtraction — so it is 8 × 3 × (difference of the other two)."

Optiver Make 24 Mental Math: Common Mistakes

Random operation trying. Combining numbers arbitrarily and hoping is slow and looks panicked. Always work backward from 24's factorisations.
Forgetting a number or reusing one. Each number exactly once — track which you have used, especially under pressure. A quick recount before announcing saves embarrassment.
Going silent. Narrate your search: "I am trying to make 12 from these two..." Silence suggests you are stuck; narration shows method even mid-search.

Make-24 rewards structured thinking over raw speed — the candidate with a system beats the faster but random calculator.

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FAQ

What are the rules exactly? Four numbers, each used exactly once, combined with +, −, ×, ÷ (and parentheses) to make 24. Standard interview versions use single-digit or small numbers.

What if I cannot find a solution quickly? Keep narrating and try the next factor pair. Interviewers value the systematic search; a candidate who works through factorisations methodically impresses even when slow.

Are all sets solvable? Not all — but interview sets are chosen to be solvable, usually via clean factorisations. If you are truly stuck, say which factor pairs you tried and why they failed.

How do I practise? Use Make-24 apps or card decks (any four cards, face values), timed. Practise the target-first habit until factor pairs of 24 are automatic.

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