Solving an equation with five odd numbers

Proved

WorkbookSource.problem_3486

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

lean-workbooksource-checked

If $991+993+995+997+999=5000-N$ , then $N=$

Source: InternLM Lean-Workbook, record lean_workbook_3486 (Apache-2.0). The complete source proposition and its explicit variable declarations are preserved.

Preamble

import Mathlib
open Real Nat

Formal statement

theorem WorkbookSource.problem_3486 (N : ℕ) : 991 + 993 + 995 + 997 + 999 = 5000 - N → N = 25  :=  by sorry

Source

https://huggingface.co/datasets/internlm/Lean-Workbook/blob/main/lean_workbook.json, record lean_workbook_3486; Apache-2.0

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