• Question: How many digits of Pi can you recite off of the top of your head? (name them e.g. 3.14159265358979.......)

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      Asked by BeenP on 9 Nov 2020.
      • Photo: Sarah Brown

        Sarah Brown answered on 9 Nov 2020:

        I can only recite the first 7 digits (though it used to be more). How many can you recite? Bet it is more than me 😛

      • Photo: Eduard Campillo-Funollet

        Eduard Campillo-Funollet answered on 9 Nov 2020:

        Eight… and I know that is not much!

        But I have never been good and memorising stuff, this is one of the things I like about maths: many times you can understand maths much better than just memorising!
        For instance, I don’t know many digits of Pi but I understand how they are computed. The current “record” is 50,000,000,000,000 digits and it took a supercomputer over 300 days!

      • Photo: Chris Budd

        Chris Budd answered on 9 Nov 2020:

        3.141592653589793 …

        And yes .. I DO need to know all of these digits for my work.

        pi is very very important in communication, WiFi and in GPS .. both areas that I work in.
        Even a small error in pi gets multiplied up quickly to be a large error in the solution.
        So I need to know a lot of digits to make sure that the calculations work out.

        If you want a pretty accurate value for Pi (to 6 DP) then just remember 1 3 5

        Pi approx 355/113

        Or if you prefer .. in my opinion the best formula in the whole of maths is:

        pi/4 = 1 – 1/3 + 1/5 – 1/7 + 1/9 – 1/11 + 1/13 – 1/15 + …

        Isnt that lovely!!!

      • Photo: Tom Ranner

        Tom Ranner answered on 9 Nov 2020:

        I know 3.14159 – I’m luck to get to use a computer all day long if I need to know any more than that!

      • Photo: Chris Tognini

        Chris Tognini answered on 9 Nov 2020:

        3.14159265359… although I did round up the last digit 🙂

      • Photo: Alan Walker

        Alan Walker answered on 9 Nov 2020:

        Three. I’ve a truly shocking memory (one of the reasons I studied mathematics rather than a subject where memory is important). Knowing an approximation for pi isn’t important for the work I do, so I’ve never sat down to try to learn more.

        However, I’ve a friend who used a 20-word rhyme to learn the first 20 digits. Naturally, I can’t remember it!

      • Photo: Christos Klerides

        Christos Klerides answered on 9 Nov 2020:

        Not many! 3.14159. More important understanding the calculations in the background than memorising numbers by heart!

      • Photo: Sophie Carr

        Sophie Carr answered on 9 Nov 2020:

        A lot less that you write here! I can remember 3.142 and then I’d have to look them up.

      • Photo: Cesare Giulio Ardito

        Cesare Giulio Ardito answered on 10 Nov 2020:

        Not many (and I barely know the third digit of e!), but in today’s world it just means that the few times I need to know more digits than just “3.14” I waste two seconds typing “pi” into Google, or my calculator.

        Better be memory-efficient and remember other, less findable things!

      • Photo: Nathan Turner

        Nathan Turner answered on 11 Nov 2020:

        I only remember 3.1415 (which is enough for me!) however if I wanted to find more digits I could use one of my favourite formulae:

        pi^2 / 6 = 1 + 1/2^2 + 1/3^2 + 1/4^2 + 1/5^2 + …

      • Photo: Thomas Woolley

        Thomas Woolley answered on 11 Nov 2020:


        There is a certain rhythm to these ones that I can chant to myself.

      • Photo: Kate Elliott

        Kate Elliott answered on 16 Nov 2020:

        3.142 if I need more than that I use a pi function on my calculator!