BrainDen.com - Brain Teasers
• 0

## Question

You can use only paper and pencil. And infinite time. No other material. And you know math as much as an elementary school student. Can you tell me nearly the exact pi number after nearly infinite time?

• Created

## Recommended Posts

• 0
You can use only paper and pencil. And infinite time. No other material. And you know math as much as an elementary school student. Can you tell me nearly the exact pi number after nearly infinite time?

no

##### Share on other sites
• 0
no

I say "yes". Also I want to add that: "you don't know squareroots, trigonm. etc. you can only make (+ - / x)"

Although this is my own question and my own solution, its quite easy.

##### Share on other sites
• 0

You could get the exact number with infinite time, because pi is infinite. But I don't see how you could get "nearly exact" (although this is somewhat relative surely) with "nearly" infinite time.

Nearly infinite is kind of an oxymoron.

##### Share on other sites
• 0

pi = 3,1459.....

which digit comes after 9 ?

##### Share on other sites
• 0

pi = 3,1459.....

which digit comes after 9 ?

2

##### Share on other sites
• 0

As I said, it is easy. But not so much. Use your intelligence instead of memory.

##### Share on other sites
• 0

But pi is infinite, so even if after 3 billion years, you'd calculated pi to 5879355646271694 x 10 to the power 7836382 digits, you still wouldn't be close to a fraction of the number of digits of pi

##### Share on other sites
• 0

You're right but you missed that I'd changed my question. I don't want exact or nearly exact pi. I only want for example 12. digit of pi, after comma.

##### Share on other sites
• 0

oh, ok, that's possible then, sure

##### Share on other sites
• 0

hmmm.. there are plenty of series which tend towards pi (see Mathworld for most of them), some of which should require only elementary operations, and which, for a given number of terms, can therefore give an approximation to pi.

However, to be certain that we are sufficiently accurate for a particular digit to be correct, requires us to calculate the next term and show that it is small enough. This would mean some pretty hefty calcuations, especially as the simple series converge pretty slowly.

In hexadecimal, there's a great little formula for calcuating the 'n'th digit, but not in decimal as far as I know - but I may be wrong...

There may be some graphical/geometric way of calculating it, perhaps, which requires measurement of an object at a greater and greater scale?

##### Share on other sites
• 0

I know those magic series but I didn't know those when I was in elementary school. Maybe you knew. Anyhow, assume that this series aren't invented yet. How can you get many digits of pi?

##### Share on other sites
• 0

I press the "pi" key on my calculator.

##### Share on other sites
• 0

355/113

Edit: I mean 6

Edited by Alyanna
##### Share on other sites
• 0
You can use only paper and pencil. And infinite time. No other material. And you know math as much as an elementary school student. Can you tell me nearly the exact pi number after nearly infinite time?

I kind of did this with my Dad when I was 3.

Pi number is 3.14152429

I did this by rolling tins, plates (but not pie unfortunately)

Also, I'm English.... is elementary school like english primary?

Any way, when I was three I only knew add and divide.

##### Share on other sites
• 0
I kind of did this with my Dad when I was 3.

Pi number is 3.14152429

I did this by rolling tins, plates (but not pie unfortunately)

Also, I'm English.... is elementary school like english primary?

Any way, when I was three I only knew add and divide.

You got pi correct to 4 decimals by measuring rolling plates?

Also, American elementary school is typically grades K-5, which is about ages 5-10.

##### Share on other sites
• 0
I kind of did this with my Dad when I was 3.

Pi number is 3.14152429

I did this by rolling tins, plates (but not pie unfortunately)

Also, I'm English.... is elementary school like english primary?

Any way, when I was three I only knew add and divide.

If your method is perimeter/diameter, then you can't achieve more then 3 decimals, even you have eagle eyes. But if your method is different, please write it. I know a method by using pins. You draw parallel lines on the ground and let a pin to drop on it, then count the ones that touch the lines and not touch the lines. Their proportion gives the pi number. This is a known method, and gives pi excellent. But my rule was using nothing other than a paper and pencil to write on it. I mean you can do only calculations (+-/x). A 12-13 years old child can do it. By the way your pi is wrong after 5. decimal, pi=3.14.59265.

##### Share on other sites
• 0

pi = 3,1459.....

which digit comes after 9 ?

I would ask a different question:

What digit actually comes after the 4?

##### Share on other sites
• 0
I would ask a different question:

What digit actually comes after the 4?

Excuse me, I omitted 1.

pi=3.14159265

##### Share on other sites
• 0

gng astray the topic,

I recollect the mnemonic to remember the value of pi

"How I wish I could calculate pi"

which is 3.141592

##### Share on other sites
• 0
gng astray the topic,

I recollect the mnemonic to remember the value of pi

"How I wish I could calculate pi"

which is 3.141592

I can't consider a mnemonic for it.

You should simply memorize it.

Yes, I've a method to calculate it without using anything, and with only (+-X) operations (not /) .

But it is very time consuming, thus I don't advice it.

##### Share on other sites
• 0
I can't consider a mnemonic for it.

You should simply memorize it.

Yes, I've a method to calculate it without using anything, and with only (+-X) operations (not /) .

But it is very time consuming, thus I don't advice it.

I remember there being a Monte Carlo method for the calculation of pi, where you randomly drop toothpicks on a grid of parallel lines where the distance between lines is the same as the length of the toothpick. The ratio of twice the number of toothpicks dropped divided by those that fell and intersected a line converges to pi.

##### Share on other sites
• 0
I remember there being a Monte Carlo method for the calculation of pi, where you randomly drop toothpicks on a grid of parallel lines where the distance between lines is the same as the length of the toothpick. The ratio of twice the number of toothpicks dropped divided by those that fell and intersected a line converges to pi.

I mentioned that method above but I wanted you to get pi without using anything other then a paper and a pencil, both are infinite, and you have a lot of time. Dropping the pencil on the paper is a method but I want you to make only calculation (+-x operations). Monte Carlo method is a magic and an easy method. Few people are aware of it, thus I congratulate you. But I am still asking a method with only calculation.

##### Share on other sites
• 0

3ยท1415926535897922

##### Share on other sites
• 0

Heres a good one

3.141592653589793238462643383279502884197169399375105820974944592307816406286208

998628034825342117067982

##### Share on other sites
• 0
Heres a good one

3.141592653589793238462643383279502884197169399375105820974944592307816406286208

998628034825342117067982

## Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

×   Pasted as rich text.   Paste as plain text instead

Only 75 emoji are allowed.

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×