# How many decimals of Pi do you remember?

i remember:
pi=3.14159
e=2.718282
thats odd. i remember one more digit of e than of pi.

3.14159
1.414
299,792,4458 m/s
2.718

That is all I remember off hand

3.1415926535897932384626 (is that right?), then im lost. Sometimes I can do more but without confidence.

In a humbling experience, I typed Pi[1,000,000] into Mathematica and it returned a few dozen digits of Pi asking if I really wanted it all. After I told it I wan't kidding it delivered all one million digits in a few seconds.

I don't understand why people waste their time remembering the decimals of Pi, do something productive that will actually be of value!
I saw this post yesterday and thought; maybe I should look at this pi! Doesn't take that long memorising raw numbers, now I know:
3.
1415926535 8979323846 2643383279 5028841971 6939937510 5820974944 59

I am sure you know much more digits than that, associated to different things than pi though. I mean 4 digits take ~1 minute to memorize, so the above string should take roughly 15 minutes. Not that much of your life.

http://zs1.smbc-comics.com/comics/20100130.gif

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ideasrule
Homework Helper
I think the average scientist knows many more digits of pi than the average non-scientist, just because they use the number more often.

I doubt that there is any scientist who knows less than 3.14.

dlgoff
Gold Member
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Redbelly98
Staff Emeritus
Homework Helper
I think the average scientist knows many more digits of pi than the average non-scientist, just because they use the number more often.
I doubt that there is any scientist who knows less than 3.14.
I add a couple of digits every decade or so. Now in my late 40's, I have 8 or 9 digits memorized.

In actual practice, my calculator has a π button clearly labeled. Instead of spending time memorizing many digits, I have memorized the following:
• In Excel, =pi() results in π
• if I don't know whether pi is defined in a given computer language, defining a variable ppii=4.*atan(1.) always works

I've always known pi up to 15 digits or so, but I was never the type of guy who would memorize pi to a few hundred decimal places. I'd rather memorize the scale of everything in the universe from plank length to the size of our observable universe, the mass and half life of elements, reference numbers in physics, the names of stars, etc.

Edit: Memorized it to 100 digits just now to test my memory.
http://www.greenpeninc.com/memorize/memorize.php
Now trying to memorize e and phi to 100 digits just for amusement. Darn you PF!

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Felipe61
must get really old now.. i only remember 3 decimals of pi.

must get really old now.. i only remember 3 decimals of pi.
if you remembered 3----would they still be called decimals?

(i just know one decimal of pi)

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if you remembered 3----would they still be called decimals?

(i just know one decimal of pi)
So, you say 3.1?

So, you say 3.1?
the (one) decimal is the decimal (point/dot)

Gokul43201
Staff Emeritus
Gold Member
I saw this post yesterday and thought; maybe I should look at this pi! Doesn't take that long memorising raw numbers, now I know:
3.
1415926535 8979323846 2643383279 5028841971 6939937510 5820974944 59

I am sure you know much more digits than that, associated to different things than pi though. I mean 4 digits take ~1 minute to memorize, so the above string should take roughly 15 minutes. Not that much of your life.
I don't think I could do it in 15 minutes if I tried right now. And probably not in an hour even - unless I figure out some clever trick to memorize it. In general though, the way I memorize things is by seeing/using them periodically (i.e., through familiarity). I'm terrible at committing to memory by repeated recitation, like I've seen others do, but that's also probably because I have not put much effort into developing that skill.

I don't think I could do it in 15 minutes if I tried right now. And probably not in an hour even - unless I figure out some clever trick to memorize it. In general though, the way I memorize things is by seeing/using them periodically (i.e., through familiarity). I'm terrible at committing to memory by repeated recitation, like I've seen others do, but that's also probably because I have not put much effort into developing that skill.
The trick is to want to memorize, at least for me. If I don't care I will only remember bits but when I focus I can remember just about anything indefinitely. The problem is of course that you can't just conjure up such focus at will.

But are you certain you can't do it? I really wonder how peoples memories works, since they seem to forget just about anything all the time... How do you even study with that disability? It would force you to do the same thing over and over again only to know that it still wont all stick. Kinda like shovelling raw rice with a fork!

Not intending to offend, I really wonder. I'd guess that they are just insanely passionate/motivated about it so they continue on anyway, but it is hard to accept that people have to forget just about everything. Seems so counter intuitive, I am hoping that there is a switch those haven't found yet and if they flip it they would stop forgetting important things.

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I've memorized thousands of digits of Pi just fine.
But it's the digits to the right of the radix that I have trouble with.

Or.

I've memorized every digit of Pi.
Putting all ten of them in sequence is harder.

Pi is a lot easier to remember if you calculate with pi basis:
1.0000000000000000000000000000000000000000000000000000000000000000000000000000000000000....

Pi is around 3-ish.

Pi is around 3-ish.
3.ish

I just find that learning pi is a good way to maintain your memory active, plus it's a really good time waster. I found out that now i can remember series of numbers in a lot less time. I just use birthdates, repeating numbers, and my latest, pattern you do with your fingers when you type the keys on the numpad.
I agree. I did the same thing between classes when I was in school towards the end of the semester. I got to 108 places.
I did it as an exercise because I had always told myself I had a terrible memory and I wanted to see how bad my memory was. The semester ended when I was at 108 numbers (I think) and so I stopped the exercise.
There are people who can memorize pi to 10,000 places. I suppose I could have gotten much farther if I made the time to do so. I gained a block of seven numbers daily and that was the 'trick' to it. Also I made it into a rythm like which is a second trick. I think seven numbers at a time contain a rythm and that rythms aid memory and this is why groups of seven numbers pop up a lot. I don't mean anything dumb like numerology, I am talking about the rythm they make and how that aids memory.

I still remember 18 places after the 3.
I think I could have gone much further had I made the effort.

Its a valuable exercise for people interested in their own memory. I didn't read this entire thread but I bet 90% of the comments were like this: "Why do that? It's stupid. That number is not useful to that many places!" The point is not the number but I think that testing one's own memory is useful and it doesn't matter what the object of that memory is. It could be zip codes or sports stats.

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