See also the Dr. Math FAQ: 3D and higher Browse Middle School
Prime Numbers Stars indicate particularly interesting answers or
good places to begin browsing. Selected answers to common
questions: Testing for primality. - Prime or Composite?
[09/30/1997] Wouldn't every number be composite? - Primes and
Repeating Unit Numbers [12/09/1998] How do you prove this
statement: For every prime number there exists a repeated unit
number that is a multiple of that prime. - Products of Digits
[03/02/2003] The product of digits in the number 234 is 24:
2*3*4 = 24. Can you describe a general procedure for figuring
out how many x-digit numbers have a product equal to p, where x
and p are counting numbers? How many different three-digit
numbers have a product equal to 12? to - Proving a Number is
Prime [10/13/2004] How do you really prove that 2 or some other
number is a prime number? - Pythagorean Triples [04/14/1997] Why
can't all the numbers in a Pythagorean triple be prime? -
Relatively Prime [10/07/1999] What does the t