# Top Ten: Mathematical celebration days

The definitive chart of the best dates

This issue, Top Ten features the top ten geometry instruments! Then vote here on the top ten units for Issue 08!

Reentering the top ten, it’s the day of monthly MathsJam: the second last Tuesday of the month.

At 9 this issue, the favorite day of fans of the American date format and decimals: Pi day (14 March).

A new entry at 8: Hannah Fry’s birthday, or Fryday (21 February).

At 7, it’s the day commemorating physicists trying to do infinite series: sum of all the negative integers day (1 December).

At 6, it’s a celebration for people who’d rather have two pies: Tau day (28 June).

At 5, it’s the favourite day of people who like good date formats and fractions: Pi approximation day (22 July).

At four, it’s 25 December, the day we celebrate the birth of our lord and saviour: Sir Isaac Newton’s birthday.

At 3, it’s days like 15 August 2017 ($15^2+8^2=17^2$): Pythagorean triple days.

At two, it’s the Chalkiest day in March: 13 March.

There’s an approximately 1 in 365.25 chance that the picture for this issue’s number one is relevant: it’s today, because every day is a great day for maths.

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