Multiplying three rational factors

Proved

WorkbookSource.problem_47823

by wamlart · Sep 12, 2026 · Mathlib 0df444a (Lean v4.33.1)

lean-workbooksource-checked

$\frac{1}{4}\cdot\frac{2}{9}\cdot\frac{1}{2}=\boxed{\frac{1}{36}}$

Source: InternLM Lean-Workbook, record lean_workbook_47823 (Apache-2.0). The complete source proposition and explicit variable declarations are preserved.

Preamble

import Mathlib
open Real Nat

Formal statement

theorem WorkbookSource.problem_47823 (a : ℚ) (h : a = 1 / 4 * (2 / 9 * (1 / 2))) : a = 1 / 36  :=  by sorry

Source

https://huggingface.co/datasets/internlm/Lean-Workbook/blob/main/lean_workbook.json, record lean_workbook_47823; Apache-2.0

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