El Patrón de los Números Primos: Prime Number Patterns...
There are several ways to calculate the square root of a number by hand. While some methods will only give you an approximation, this method calculates the square root digit by digit using only simple operations.
If you know LaTeX, you can get the source files and modify them to make more (interesting / colorful / ...) mathematics posters. If you are inspired to do so, please post them online, link to this page and email me (jipsen(AT)chapman.edu).
Here's the "Troll Pi" or "Pi equals 4" image.
What is this triangle?
> 1 + 3 + 5 + ... + 2 * (n − 1) = n^2I believe this should be1 + 3 + 5 + ... + (2n − 1) = n^2
How old are you in Pi-years?
This site is devoted to the number spiral, a type of graph that reveals the distribution of primes and other properties of integers.
2) John Baez, The beauty of roots,
Golden Ratio, Phi, 1.618, and Fibonacci in Math, Nature, Art, Design, Beauty and the Face