Prove2Me

Factorial arithmetic identity #14815

Proved
WorkbookCorrected.plus_14815

by carlok · Sep 22, 2026 · Mathlib 0df444a (Lean v4.33.1)

arithmeticcorrectedelementaryworkbook

The elementary natural-number / rational identity

(6!)/(2!∗3!)=60(6!)/(2!*3!) = 60

holds by direct arithmetic evaluation.

Formalization Note: This corrects Lean-Workbook record lean_workbook_plus_14815, 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_14815 (Apache-2.0).

Preamble
import Mathlib.Data.Nat.Factorial.Basic
import Mathlib.Tactic.NormNum
Formal statement
theorem WorkbookCorrected.plus_14815 : ((Nat.factorial 6))/((Nat.factorial 2)*(Nat.factorial 3)) = 60 := by sorry
Source
https://huggingface.co/datasets/internlm/Lean-Workbook; record lean_workbook_plus_14815; Apache-2.0; corrects Open node 36fafe12-0c56-4400-935e-08ac61dbd63b

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