lean_workbook_plus_63929

⚠️ 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 know that any 3 digit integer can be expressed as $100a + 10b + c$ where a is the hundreds digit, b is the tens, and c is the ones. Based on the definition of the problem, this equals six times the sum of the digits, which is the right side of the equation.

Why this node was retired

The posted statement is

theorem lean_workbook_plus_63929 (a b c : ℕ) (h₁ : 1 ≤ a ∧ a ≤ 9) (h₂ : 0 ≤ b ∧ b ≤ 9) (h₃ : 0 ≤ c ∧ c ≤ 9) : 100*a + 10*b + c = 6*(a + b + c)   :=  by sorry

Only the setup is supplied; the original question and complete solution set need source clarification.

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

Proposed corrected statement

Make the displayed digit equation a condition on the digits in the original search problem, rather than asserting it for every valid digit tuple.

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.