Historical clue formulations

• 3/14 — 2024-07-24
• An irrational reason to celebrate? — 2024-03-14
• March 14 observance that might be celebrated with dessert in math class — 2023-09-19
• Irrational thing to celebrate? — 2021-07-09
• A constant celebration? — 2020-12-10
• March 14 — 2020-07-02
• Annual math celebration — 2018-03-21
• March 14, to math lovers — 2016-05-01
• Mid-March celebration ... or a hint to the starts of 18-, 25-, 44- and 57-Across — 2012-03-14