Better File Cabinet 2026by Eric Hsu

Overview

Better File Cabinet 2026 is a modernized interface for the long-running Better File Cabinet of math problems. It focuses on fast search, filtering by tags and course, and tools for building custom worksheets from a large corpus of carefully curated problems.

Site features

• Search with words (e.g. "related rates").
• Regex search by wrapping a pattern in /.../, for example /quad.*ratic/.
• Filter by tags with comma-separated tag names such as limit, absolute-value.
• Filter by course using the Course dropdown to focus on Calculus I, Precalculus, etc.
• Add to cart to collect problems, then export the cart as a LaTeX worksheet.
• Find similar to see other problems with related wording and structure.
• LLM answers to see what your students will see if they copy the problem into an LLM.

To Do

• Most of the problems are not tagged. The tagging was the result of a summit of Emerging Scholars Program instructors in the 2000s.
• There are a few more problem collections I want to add to BFC, for instance Calculus II problems and a bunch of MAA problems.

Change History

• (2025-12-05).
  • Added LLM generated answers to every problem.

    Past BFCs never had answers because I didn't want students to use the site for easy answers that wouldn't let them exercise their brain. Well since 2024, students can copy and paste the problem into a free LLM and get the answer right away.

    So now you can see for any problem how a typical LLM answers it without the hassle of typing it in yourself. The answers were mostly written by deepseek-r1:8b with help from openai/gpt-oss-20b and picture-based problem solving by google/gemma-3-27b-it.

    NO ONE HAS CHECKED THESE ANSWERS. And if I ever do find a mistake, I will leave it in there moo haha, so use your brain.

    If you export your cart as LaTeX, the LLM Answers are included as comments.

  • Shareable URLs. So you can copy the URL of a search or your cart and use it to re-open that same search or cart. You can also use it to share carts of problems.
  • TikZ rendering via TikZJax.
  • Fuzzy search for main search bar. I think this is a good feature.
    
• (2025-12-01) BFC 2026 Flask backend, SQLite database, MathJax rendering of LaTeX problems. Same old features: search by text, tag, course; shopping cart. Migrated problems from old BFC. New feature: similarity search to find text similar problems.

For a detailed historical record and roadmap, see the original History and Plans page for the Better File Cabinet. At a high level, that document traces:

• Early versions of the Better File Cabinet and the motivations for organizing problem sets online.
• Incremental improvements across BFC3 and BFC4, including new interfaces and data conversions.
• Plans for consolidating multiple problem sources and tools into a unified platform.
• Longer-term ideas for sharing resources with teachers and researchers in a sustainable way.