lean_workbook_plus_78722

⚠️ Retired — specification defect

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

No matter which number is rolled the first time, there is a $\frac{1}{6}$ chance that the second number is the same. This leaves us with a $\frac{5}{6}$ chance that the two are different. By symmetry, there is a $\frac{5}{12}$ chance that the second number is greater. (There is the same chance that the second number is less.) The probability that the second number is greater than or equal to the first is then $\frac{1}{6}+\frac{5}{12}=\boxed{\frac{7}{12}}$

Why this node was retired

The posted statement is

theorem lean_workbook_plus_78722 :
  (1/6 + 5/12) = 7/12   :=  by sorry

The stored statement only checks0+0=0; the intended fractional equality is also elementary.

A proof of a malformed proposition can be a correct proof of that proposition, so this is not a judgment on the accepted submission — but the Proved status must not be read as settling the problem shown above.

Proposed corrected statement

Type the probability arithmetic in ℚ or ℝ: (1/6:ℚ)+5/12=7/12.

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.