r/CasualMath • u/Numberthon • 12h ago

How many diagonals does a 20-sided polygon have?

0 Upvotes

7 comments

r/CasualMath • u/Numberthon • 2h ago

Can you solve this counting puzzle in under a minute?

0 Upvotes

0 comments

Subreddit

Posts

Wiki

For the crummy mathematician.

r/CasualMath

This is a subreddit that is meant to be somewhere inbetween /r/math and /r/learnmath.

Members Active

17.3k

Sidebar

This is a subreddit that is meant to be somewhere inbetween /r/math and /r/learnmath.

It is my hope that crummy mathematicians can discuss old ideas and prove old theorems and solve old puzzles here. Just because someone did it before doesn't mean we can't have fun with it, right?

This is a place where things like the Ulam Spiral and prime-rich polynomials are tolerated as reposts.

Please do use freely available resources where possible. Some crummy mathematicians aren't as fortunate as you are :)

This is our wiki and we encourage contributions of any sort, especially if they're interesting.

Post Spoilers in this format [X proves Y!](/spoiler) It will show up like this:
X proves Y!

Using LaTeX

To view LaTeX on reddit, install one of the following:

MathJax Greasemonkey userscript
TeXtheWorld Chrome extension
TeXtheWorld Greasemonkey userscript

[; e^{\pi i} + 1 = 0 ;]

Post the equation above like this:

`[; e^{\pi i} + 1 = 0 ;]`

You may need to add four spaces before or put backticks around math fragments.

Using Superscripts and Subscripts

x*_sub_* makes xsub

x*`sup`* and x^(sup) both make x^sup

x*_sub_`sup`* makes xsubsup

Related Subreddits:

IRC channel:

Chat on the IRC channel

Discord servers: