# Flipping a fair coin... 2 different probabilities?? **URL:** \ **Category:** Factual Questions\ **Created:** [April 22, 2001, 6:15pm UTC](https://boards.straightdope.com/t/flipping-a-fair-coin-2-different-probabilities/62895 "2001-04-22T18:15:36Z")\ **Posts on this page:** 3\ **Page:** 2
**Author:** ![AWB](https://avatars.discourse-cdn.com/v4/letter/a/bb73d2/32.png) [@AWB](https://boards.straightdope.com/u/AWB)\ **Post date:** [April 23, 2001, 4:16pm UTC](https://boards.straightdope.com/t/flipping-a-fair-coin-2-different-probabilities/62895/21 "2001-04-23T16:16:40Z")
> [@](#): > > \*Originally posted by jcgmoi \* > \*\ ***AWB** , [here’s](http://www.unc.edu/~rowlett/units/large.html) a site that identifies 10[sup]30[/sup] as a nonillion (no ‘t’), with regular intervals up to 10[sup]93[/sup], which is a trigintillion. \*\* Ah, thanx. The number 2[sup]100[/sup] is then properly called: 1 nonillion, 267 octillion, 650 septillion, 600 sextillion, 228 quintillion, 229 quadrillion, 401 trillion, 496 billion, 703 million, 205 thousand, 376 :D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D ---
**Author:** ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)\ **Post date:** [April 23, 2001, 7:58pm UTC](https://boards.straightdope.com/t/flipping-a-fair-coin-2-different-probabilities/62895/22 "2001-04-23T19:58:56Z")
> [@](#): > > What are the chances a coin would come up heads consecutively 101 times? If heads and tails really are equally likely, then the probability of getting heads 101 times in a row, while teeny-tiny, is exactly the same as the probability of getting head 100 times in a row followed by one tail. The next time you’re playing poker, look at the five cards you were dealt and say, “Wow! The odds of this happening are 2,598,959 to 1!” (Those are the odds of getting those particular five cards, no matter which cards they are.) ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [April 23, 2001, 11:31pm UTC](https://boards.straightdope.com/t/flipping-a-fair-coin-2-different-probabilities/62895/23 "2001-04-23T23:31:16Z")
The odds of flipping 101 heads in a row is very very small. BUT, the odds of flipping 101 heads in a row, _given_ that you have already flipped 100 in a row is 50%. Once the first 100 flips have already happened, you know the outcome, so the probability of their being heads is 100%. [Previous page](https://boards.straightdope.com/t/flipping-a-fair-coin-2-different-probabilities/62895.md?page=1)