See also the Dr. Math FAQ: 3D and higher Browse Middle School
Number Sense/About Numbers Stars indicate particularly
interesting answers or good places to begin browsing. Selected
answers to common questions: Multiplying by zero. Casting out
nines. Number facts from the Web. - Facts about e [11/09/1998]
Where does the number "e" come from and what uses does it have
in the - Figurate and Polygonal Numbers [11/21/1998] I need to
know everything about figurate numbers. - Figurate Numbers
[12/31/1997] Questions about figurate numbers (triangular,
square, pentagonal)... - Finding Input-Output Rules [10/08/2003]
My 3rd grader is having trouble finding rules to change one list
of numbers (the inputs) into another (the outputs)... - Finding
n(n-1)/2 in the Real World [09/14/2002] How can n(n-1)/2 be
explained in common everyday language? When is - Finding Pi
[11/14/1997] What is the quickest algorithm for finding pi? -
Finding the Digit of a Decimal Expansion [11/14/1998] What digit
will appear in the 534th place aft