We don't have too many math puzzles - they're all derived from the sci.math newsgroup. Please visit the "Links" section if you're interested in finding puzzles posted by others.

From Usenet, sci.math:

1. ("Unsolvable Geometry Problem")…Divide a circle into four pieces of equal area by means of three lines (not straight lines) of equal length. Answer:
2. ("Complex Analysis Problem")….Prove that the function exp(z) = 2z + 1 has one and only one solution inside the unit disk ( |z| = 1.) Answer:
3. ("Functional Equation")… What function f of x satisfies f(x)*f(x^2) = 1/(1-x) ? Incomplete Answer:
4. ("Palindrome Problem")….Problem Stated.
5. ("A Nonlinear Differential Equation")….Problem Stated.
6. (Simple geometry proof)….Problem Stated.
7. (Geometric brain teaser)….Problem Stated.
8. (Integer puzzle)….Problem Stated.
9. (Number array puzzle)….Problem Stated.
10. (Classic number puzzle)…How do you buy 100 birds for $100, when chickens cost $.50, ducks cost $3, and turkeys cost $10? Answer:
11. (Functional puzzle)….Problem Stated.
12. (Differential Equation) :Solve :y'' + sin(y) = 0 for the interval [0,1] given y(0) =a and y(1) = b. Incomplete Answer:
13. (Differential Equation) :Solve : dy/dx = exp(y/x) Incomplete Answer:
14. (Another "simple" geometry proof)….Problem Stated.
15. (Formula for sum of x^a for x = 1..n) …. Answer:
16. (Integers and irrationals)….Problem Stated. .... Answer.