lean_workbook_plus_893

⚠️ 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.

The probability that LuLu wins on the first round is $\frac{6+4}{36}=\frac{5}{18}$ . The probability that LuLu loses on the first round is $\frac{1+4+1}{36}=\frac{1}{6}$ . Thus, the probability that LuLu does not win or lose on the first round is $1-\frac{5}{18}-\frac{1}{6}=\frac{5}{9}$ .

Why this node was retired

The posted statement is

theorem lean_workbook_plus_893 :
  1 - (6 + 4) / 36 - (1 + 4 + 1) / 36 = 5 / 9   :=  by sorry

Evaluate all fractions and subtraction in ℚ or ℝ; a full probability theorem additionally needs the game model.

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

Proposed corrected statement

Evaluate all fractions and subtraction in ℚ or ℝ; a full probability theorem additionally needs the game model.

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.