The Headlands Technologies Probability & Mental Math interview is stage 3 of 5 in the Headlands Technologies interview process, after the Online Assessment / Coding. Format: 45-60 min - video. Probability, expectation, combinatorics, and brain-teasers with follow-ups.
Preparing for this round? Practice the 16 questions mapped to the Headlands Technologies Probability & Mental Math, with worked solutions. A free account saves your progress.
What the Probability & Mental Math tests
QuantVault maps 16 practice problems to this round. By topic, the biggest groups are probability (7), brain teasers (3), combinatorics (3), expectation (3); by difficulty, 4 easy, 12 medium and 0 hard. 1 of them were reported by candidates who interviewed at Headlands Technologies, most recently in Jul 2026.
How to prepare for the Probability & Mental Math
- Estimate first, then formalize.
- Order statistics + waiting times recur.
- Expect follow-ups extending the result.
Further reading: Mental math for trading interviews · How quant superdays work · Behavioral questions at trading firms · Market-making game interview guide.
Question types in this round
The 4 largest question types in the Headlands Technologies Probability & Mental Math practice set; across them the most common sub-topics are discrete probability, conditional probability, symmetry, expected value, Bayes' theorem, independence. The questions themselves, with worked solutions, are in the round practice.
Probability7 in this round
Brain Teasers3 in this round
Combinatorics3 in this round
Expectation3 in this round
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Frequently asked questions
What is the Headlands Technologies Probability & Mental Math interview?
It is stage 3 of 5 in the Headlands Technologies interview process, after the Online Assessment / Coding. Format: 45-60 min - video. Probability, expectation, combinatorics, and brain-teasers with follow-ups.
How long is the Headlands Technologies Probability & Mental Math interview?
Candidates report: 45-60 min - video.
What questions come up in the Headlands Technologies Probability & Mental Math interview?
The practice set QuantVault maps to this round centers on probability, brain teasers, combinatorics.
How should I prepare for the Headlands Technologies Probability & Mental Math interview?
Estimate first, then formalize. Order statistics + waiting times recur.
What comes after the Probability & Mental Math?
The Statistics & Modeling (stage 4 of 5). Format: 45-60 min - video.
Practice the Headlands Technologies Probability & Mental Math round
Work the 16 mapped practice problems with progress tracking, then move to the next stage of the Headlands Technologies funnel.