Datasets:
Thinking Benchmark (corrected solutions)
Competition-mathematics problems for studying how long frontier models reason, measured against the shortest published human derivation of each problem.
This is a corrected release of tyrtleli/thinking-benchmark-90. Problems and answers are unchanged; the MATH-500 and FrontierMath-style problems are removed. The canonical solutions are corrected so that every solution is a complete, standalone, published human derivation of its own problem.
Contents
40 problems: 28 from AIME 2026 (I and II) and 12 from HMMT February 2026. The original release's MATH-500 and FrontierMath-style problems are not included.
| Source | Problems | Solutions from |
|---|---|---|
| AIME 2026 | 28 (all of I except #15; all of II except #2) | AoPS Wiki community solutions |
| HMMT February 2026 | 12 (Algebra & NT #4, Combinatorics #5–9, Geometry #5–10) | HMMT's official solutions |
Fields
| Field | Description |
|---|---|
id |
Problem identifier, e.g. aime_2026_i_01 |
source, domain, difficulty, difficulty_label |
As in the original release |
problem |
Problem statement (LaTeX) |
answer, answer_type |
Gold answer and its format |
solutions |
JSON list of canonical human solutions |
solution_count |
Number of solutions |
solution_tokens_min, solution_tokens_max, solution_tokens_mean |
Solution lengths in o200k_base tokens (tiktoken) |
solution_source |
Where the solutions come from (new in this release) |
Corrections relative to the original release
Rule: every solution must be a complete, standalone derivation of its own problem, from a published human source.
AIME
| Problem | Change | Reason |
|---|---|---|
| I-5 | Dropped the solution beginning "Let the complex numbers that represent $A,B,A',B'$" | Skips its key step ("after some hacking") and never reaches the answer |
| I-14 | Dropped the solution beginning "idk what the above guy is doing but" | Unfinished: sets up the equations and stops without solving them. It had been the shortest solution (454 tokens, against 946 for the shortest complete one) |
| II-9 | Dropped the solution beginning "Like in solution 1, we see that we just have the sum" | Continuation of solution 1; ends "Continue as followed." without an answer |
| II-11 | Dropped the solution beginning "We continue with the first solution" | Continuation of solution 1, not a standalone derivation |
| II-11 | Removed the solutions beginning "Choose face $ABC$ as the base." and "We let $AB$ be the side of length $10$" | Both solve II-12 (a tetrahedron; answer 223; II-11's answer is 132) |
| II-12 | Added the solution beginning "We let $AB$ be the side of length $10$" | Its own solution, previously filed under II-11 (the other was already listed) |
| II-13 | Dropped the solution beginning "We let $AB$ be the side of length $10$" | A copy of that II-12 solution (answer 223; II-13's answer is 107) |
HMMT (all 12 problems). The original release's HMMT solutions were condensed plain-text rewrites of HMMT's official solutions, a median of about 60% of the official length (as little as 20%), so they understated the shortest human derivation. They are replaced by the official solutions, taken as text from HMMT's published solution PDFs. The math is as the PDF renders it (Unicode, not LaTeX), and a few superscripts and binomials flatten in extraction. Each solution was checked to reach the official answer.
Caveats
- 11 of the 40 problems have only one solution, so for those the shortest solution is not a minimum over several.
- AIME 2026 II #10 is stated here as "the greatest possible value of $BC$" (answer 340). At least one other public transcription asks for "the sum of all possible values" (answer 850). The problem, answer and solutions in this release are consistent with each other.
Source copyright
Problems and solutions are drawn from public competition archives and remain subject to their original copyright:
- AIME problems © Mathematical Association of America (MAA); AIME solutions from the Art of Problem Solving Wiki community
- HMMT problems and official solutions © Harvard-MIT Mathematics Tournament
The dataset compilation (metadata and annotations) is released under CC BY 4.0.
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