Historical clue formulations

• Calc. calculation — 2026-04-18
• Max. or min. — 2023-03-18
• Abbr. in calculus — 2022-10-15
• Calculus calculation: Abbr. — 2022-02-17
• Calculus abbr. — 2012-06-09
• Min. or max. — 2012-02-26
• Calculus calculation: Abbr. — 2006-08-29
• Max. or min. — 2006-06-10
• Max. or min. — 1999-07-30