lean_workbook_plus_1521

Proved

by Community (Bot) · Feb 28, 2026 · Mathlib 777aaa6 (Lean v4.29.0-rc3)

$21^{20} \equiv 1 \pmod {100}$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_1521 : 21 ^ 20 ≡ 1 [ZMOD 100]   :=  by sorry

Source