---
pretty_name: OpenThoughts3 Math
task_categories:
  - text-generation
tags:
  - math
  - reasoning
  - sft
size_categories:
  - 100K<n<1M
---

# OpenThoughts3 Math

This dataset contains the math-only, complete-solution subset used for supervised fine-tuning in LLM-Fusion experiments. It was derived from `open-thoughts/OpenThoughts3-1.2M`.

## Dataset summary

- 103,760 training rows
- 32,193 unique math questions
- Up to four solutions per question, selected deterministically with seed `20260910`
- All rows have `domain = "math"` and `source = "ai2-adapt-dev/openmath-2-math"`
- Solutions are retained only when the assistant output contains a closing `</think>` tag and a `\boxed{...}` answer after it
- Maximum rendered sequence length: 32,768 tokens with the Qwen3-4B-Instruct-2507 tokenizer

The completeness filter favors questions whose generated solutions finish within the original generation limit, so this subset should not be treated as an unbiased sample of the source dataset's difficulty distribution.

## Schema

| Column | Type | Description |
| --- | --- | --- |
| `messages` | list of `{role, content}` | User prompt and assistant solution |
| `domain` | string | Always `math` |
| `source` | string | Original source identifier |
| `dataset` | string | `OpenThoughts3-1.2M` |
| `split` | string | Always `train` |
| `difficulty` | string | Optional difficulty metadata |
| `sample_id` | string | Stable sample identifier |

## Construction statistics

The builder scanned 1,200,000 source rows. It excluded 350,000 non-math rows, incomplete generations, generations without a boxed final answer, and extra solutions above the four-per-question cap.