# Without looking it up, to how many digits after the decimal point can you recite for the value of Pi?

Asked by LuckyGuy (35773) March 6th, 2015

I readily admit to being a bit of a geek. I know it to 18 digits after the decimal. I know a guy in school who knew it to 100 digits. He worked at it.
How many places can you recite without looking?
Pi day is coming up on 3/14/15. You might as well learn an extra digit to flex your gray matter. Consider it exercise.

Can this be used as a brain function test?

Observing members: 0 Composing members: 0

Those long winter nights must just fly by.

ucme (45952)

7.

I’ve been seeing all the ads for “once in a century Pi Day” t-shirts. I figure I’ll go for one next year that says “3/14/16 – I believe in rounding”.

zenvelo (32259)

Also 7, but I could make a guess at the 8th and 9th.

wildpotato (14911)

I always thought places 7,8,9,10 had a nice ring to them. As did 11,12, 13, 14.
I’m such a tool.

I wonder if you learned it as 22/7 you likely grew up before calculators.

@ucme long, miserable, and cccoold.

LuckyGuy (35773)

Due to this….

24.

It’s catchy.

longgone (13729)

5

johnpowell (15968)

@longgone That is hilarious I’m afraid I might pick up a few additional thanks to you.

@johnpowell Me too. No doubt, some multiple of Pi times.

LuckyGuy (35773)

^You’re welcome!

longgone (13729)

All of them.

ragingloli (43439)

3, no 4, ah, 5

gailcalled (54517)

16. I admit I had to confirm the last one. (I was right)

dxs (14711)

The value of pie, £2.99 steak & kidney.

ucme (45952)

Two. Anything more is just window dressing.

dappled_leaves (15839)

Only if I sing this song…by Kate Bush https://www.youtube.com/watch?v=kZSHr5E7fZY

cazzie (24503)

Just the two!

Dutchess_III (38013)

I know to 10.

osoraro (2861)

You would have to tone down your geek factor by several orders of magnitude to be only “a bit of a geek”.

I “know” π to four significant digits, but when I need to use it in calculation I either use Excel’s built-in PI() function, or the fractional equivalent: 355/113 (a better approximation than the rougher-but-easier 22/7).

CWOTUS (26062)

@CWOTUS You knew I’d have to run the numbers.
22/7 is “close” at 0.04025% high.
355/113 is “really close” at 8.4913 E-006% high, or better than 0.00001%.

LuckyGuy (35773)

Only 12 digits… but since most of the machines I work on only go to 4 and few to 6, I find 12 is more than enough to properly program the parameters on a `G2` or `G3` command (those are the G-Code commands for circular interpolation) on a CNC machine.

jerv (31032)

I just asked my fiance (@Capt_Bloth) and he got 24! He says it’s because of his love of the movie Pi and familiarity with its soundtrack cover.

wildpotato (14911)

9 but only because my husband and my kids are maths geeks and keep reciting it. I’ve just learned it by osmosis…

Stinley (11486)

55.

My friend and I got competitive about this in high school. It spiraled out of control a little bit.

Mariah (25550)

^ Ding! Ding! Ding!!! I think we have a winner!!!

although we have not heard from @phinotpi, yet.

LuckyGuy (35773)

^I’d make a guess that he’d know more digits of phi than pi :P

Mariah (25550)

I know nothing about pi, but there was a savant who could recite the first 10,000 numbers of pi.

lugerruger (785)

Eight, and I have no idea why; just something I picked up.

rojo (23461)

I have the speed of light memorized for some odd reason.

Dutchess_III (38013)

@Dutchess_III I use that number often! Our clocks and timers run so fast, light travels less than one inch. (Better than 50ps resolution.)

LuckyGuy (35773)

Well, that is easy. Almost exactly 300000km/s. Really easy to remember.

ragingloli (43439)

186,000 miles per second. Also easy to remember

gailcalled (54517)

One light-year per year. Easier than easy.

CWOTUS (26062)

@LuckyGuy says that Pi day is coming up on 3/14, but the rest of the world have a problem with this. Our dates are DAY/MONTH/YEAR….. so we make an exception for the novelty value. For the rest of the world there is no 31 of April so it just looks odd, so we simply need to make an exception, for technical reasons.

cazzie (24503)

@cazzie Thank you for the exception on this auspicious day. I too am making an exception. I date data files in YYMMDDHHmm form such as: 1503140830

LuckyGuy (35773)

‘Science America’ has caught up to the rest of the world with the date and the metric system, so I know that there are exceptions, but it isn’t systemic.

cazzie (24503)