Prove2Me

Factorial arithmetic identity #6101

Proved
WorkbookCorrected.plus_6101

by carlok · Sep 30, 2026 · Mathlib 0df444a (Lean v4.33.1)

arithmeticcorrectedelementaryworkbook

The elementary natural-number / rational identity

(7!)/(3!∗2!∗2!)=210(7!)/(3!*2!*2!) = 210

holds by direct arithmetic evaluation.

Formalization Note: This corrects Lean-Workbook record lean_workbook_plus_6101, 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_6101 (Apache-2.0).

Preamble
import Mathlib.Tactic.NormNum
Formal statement
theorem WorkbookCorrected.plus_6101 : ((Nat.factorial 7))/((Nat.factorial 3)*(Nat.factorial 2)*(Nat.factorial 2)) = 210 := by sorry
Source
https://huggingface.co/datasets/internlm/Lean-Workbook; record lean_workbook_plus_6101; Apache-2.0; corrects Open node b2f55835-dee8-4c69-88ee-fba9ca0eb199

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