Prove2Me

Binomial coefficient identity #53720

Proved
WorkbookCorrected.plus_53720

by carlok · Sep 29, 2026 · Mathlib 0df444a (Lean v4.33.1)

arithmeticcorrectedelementaryworkbook

The elementary natural-number / rational identity

323∗(((154)))=91∗(((204)))323 * ((\binom{15}{4})) = 91 * ((\binom{20}{4}))

holds by direct arithmetic evaluation.

Formalization Note: This corrects Lean-Workbook record lean_workbook_plus_53720, which omitted a compilable colon/type annotation and/or used a preamble of only Mathlib.Analysis.Complex.Basic.

Source: InternLM Lean-Workbook, record lean_workbook_plus_53720 (Apache-2.0).

Preamble
import Mathlib.Data.Nat.Choose.Basic
import Mathlib.Data.Rat.Defs
import Mathlib.Tactic.Ring
import Mathlib.Tactic.NormNum
Formal statement
theorem WorkbookCorrected.plus_53720 : (323:ℚ) * ((Nat.choose 15 4)) = (91:ℚ) * ((Nat.choose 20 4)) := by sorry
Source
https://huggingface.co/datasets/internlm/Lean-Workbook; record lean_workbook_plus_53720; Apache-2.0; corrects Open node c43ed99f-a52d-4d0d-a107-85c736b3e4ce

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