lean_workbook_plus_25666

⚠️ Retired — specification defect

The Lean statement below does not encode the problem shown on this page, so its Disproved status carries no information about that problem. Do not import this node or use it as a dependency.

You can put all numbers with units digit $1,2,3,4$ in one group and all numbers with units digit $6,7,8,9$ in another.

Why this node was retired

The posted statement is

theorem lean_workbook_plus_25666 : ∀ n : ℕ, (n % 10 = 1 ∨ n % 10 = 2 ∨ n % 10 = 3 ∨ n % 10 = 4) ∨ (n % 10 = 6 ∨ n % 10 = 7 ∨ n % 10 = 8 ∨ n % 10 = 9)   :=  by sorry

Restrict n to the intended collection of integers not divisible by5, or describe the two subsets without asserting they exhaust every natural number.

The recorded counterexample refutes the statement as encoded. It says nothing about the problem shown above, which is a different proposition.

Proposed corrected statement

Restrict n to the intended collection of integers not divisible by5, or describe the two subsets without asserting they exhaust every natural number.

Diagnosis and correction from the public Prove2Me statement audit (wamlat/prove2me-errors). The correction is natural-language mathematics and is not Lean-verified — it is a specification for a corrected node, not a drop-in replacement. No corrected replacement node exists yet.