# Memorizing Pi

#### STAii

Some people try to memorize the digits of Pi, but why do they do it ?
They say that first of all some day you may use all those digits, and secondly it helps you train your memory.
I tried, i memorized the first 120 digits, then i got bored !
So, do you people think that memorizing some digits of Pi really worth it ? And is there people that memorize other constants ?
Thanks.

#### damgo

Nope... I don't think I've needed anything more than "3" since grade school. :) More accuracy than that and I use a calculator or Maple.

In physics, it does help to know important constants & conversions to a place or two, but there were some phys majors I knew as an undergrad who actually memorized many of them to 5-6 decimal places.... I could never understand that.

#### enigma

Staff Emeritus
Gold Member
3.14

If I need any more precision, I'll either be doing it on computer to begin with, or I'll just leave it in symbolic notation.

#### FZ+

Hmm... I heard somewhere than only about 10 digits of pi are required to calculate the milky way to an accuracy of the nearest metre. Anyone can confirm that? (or at least, something like it)

As a transcedent number, Pi is an ideal number for memorisation, simply due to the random quality of it's digits. There is also a large number of formulae to use to calculate them. It is also the first known transcendent number, before the likes of e etc, and hence has fascinated man for ages.

#### brum

here's how far i can go off the top of my head

3.14159265358979323846264338327950

32 digits? (after the ".")

i remember it in groups of 4

3.14159265 3589 7932 3846 2643 3832 7950 ...

so sometimes those groups of 4 get switched around by accident

i guess i just memorized 'em out of boredom, not very useful but fun to show off people, wow 'em, etc.

EDIT: 1 digit was wrong

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#### RuroumiKenshin

But it's impossible to memorize it all....none the less, I agree that it does help retain your memory. Especially, you could possibly develop edetic(sp?) memory.

#### Hurkyl

Staff Emeritus
Gold Member
I did it out of boredom. My junior high geometry class had a banner of the first 120ish digits of pi wrapped around the room (grouped in blocks of 5), so when I was bored with the lecture I'd memorize another group of 5, I eventually got the whole thing but I've forgotten much of it.

It comes in handy when I don't want to look up the syntax for the constant pi in the c++ libraries; I just assign 3.1415926535897932384626433 to some variable (I think I can still remember another 10ish, but I believe this is beyond the precision of floating point numbers).

I've memorized 10 digits of e too, but only because it's so simple

e = 2.718281828

A couple other ones are useful just so you can recognize the results of computation: golden ratio = 1.618, sqrt(2) = 1.414, 1/sqrt(2) = 0.707, pi/2 = 1.57, 2pi = 6.28

Hurkyl

#### climbhi

Originally posted by Hurkyl
A couple other ones are useful just so you can recognize the results of computation: golden ratio = 1.618, sqrt(2) = 1.414, 1/sqrt(2) = 0.707, pi/2 = 1.57, 2pi = 6.28

Hurkyl
What is the golden ratio?

#### CJames

For some reason I remember it to 3.14159, but there's no reason to. In most cases you should use [pi] anyway, since that is however accurate somebody wants it to be. If you need a decimal answer, it's called a calculator, with the little [pi] symbol on it.

#### STAii

Well.
Mainly because of boredom at school (and cause we needed to invent some game anyway) we invented a game that was based on the digits of Pi.
At the end of the first day we both had memorized the first 120 digits (want me write them ?), but then i stopped playing it.
It seems that some students at the school thought that me and my friend was playing this game to show off in front of the others that we can memorize the digits of Pi (while those people sill think that Pi is exactly 22/7, they are unable to believe that this is a very old approximantation (right word ?))
So that is the story of my trial to memorize it.

I heard that the world record of memorizing Pi is about 40,000 digits, it took the record holder more than 9 hours only to call them back to the world records comittee.

#### plus

Once memorized 1st 30 digits of pi in a night, but was too bored to do it again.

Not much use in having this knowledge. Apart from proving that I once had nothing else to do.

#### Zargawee

Well , Momorizing The Digits Of Pi Was A Very Boring Game , Specially That I Started Playing It While Other Competors Know 120 Digits Of It ...
All I Can Remember Now Is The First 20 Digits Of It ...

But In Our Life ( As Normal Human Beings ) , i Think 3.14 Is Enough , Isn't It ?

#### pmb

I guess some people try to do it just to see what they can do. Others do it maybe as a party trick - others to try to impress people. I try to memorize just the first few and I do that since I use it. I think I recall that

pi ~ 3.140159 ...

Okay - just checked - seems I was wrong. It's

pi ~ 3.141592 ....

Oh well. No party favor for me. :-)

Pmb

#### JamesBell

3.14 oh **** this you sad bastards (excluding parsons)
ok serious 3.14beef and onion stake and kindney
OK SERIOUS
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#### Parsons

Pi

i only know Pi to the first one hundred and fifty or so decimal places: 3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825342117067982148086513282306647093844609550582231...

i learnt this in an hour or so, as i was bored. i also did this to test my memory

#### STAii

Why so much people like to waste the server space by all those digits of Pi ? (J/K).

So Parsons, you agree that trying to memorize Pi is some kind of a good test for memory.

I believe that memorizing Pi actually gives you some kind of memory test that you never took before, people try to memorize 'words' (or other things) in memory tests (like Poetry for example) , but it is really rare to find a memory test where you actually only have to remember numbers !

I was welling to continue memorizing Pi, to start learning how to have a Numeric Memory , which can turn out usefull in the future (try to imagine if you could memorize the phone numbers of people just as they tell them to you !).

#### damgo

30, 100 digits in a day? You guys are fiends. I'm lucky if I can remember my multiplication tables! It's been so long since I've counted higher than 6 in a math class anyways, I'm lucky if I can get to ten....

#### JamesBell

I know pi to 10.000 characters long!!! as I have already demonstrated

#### Zargawee

30, 100 digits in a day? You guys are fiends. I'm lucky if I can remember my multiplication tables! It's been so long since I've counted higher than 6 in a math class anyways, I'm lucky if I can get to ten....
LoL

For Me It's Hard To Memorize Something , But When I memorize it , I hardly forget it ...
But in maths , I always get high marks ...

#### Viper

I know pi to about 8places

#### Mike H

There's a reason why Gaussian and H-L units are used in physics. It cuts down (Gaussian) or totally gets rid of (H-L) those darned ugly and occasionally messy 4*pi units that are ubiquitous in SI notation.

Besides, if you do enough calculations where you need pi explicitly, you'll memorize enough digits to save yourself the hassle of looking it up. Everyone I know has done as such.

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