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Browse High School Number Theory
Stars indicate particularly interesting answers or
good places to begin browsing.
Selected answers to common questions:
Diophantine equations.
Infinite number of primes?
Testing for primality.
What is 'mod'?
 One equals Two [07/25/2001]

There is an algebraic manipulation involving division by zero that
results in one equals two, or some other contradiction. What is it?
 One Plus One isn't Two [1/10/1995]

I was once shown that 1+1 isn't 2, and I don't remember how it was done.
Could you please email me with an answer?
 One to the Power of Infinity [07/03/2001]

An instructor says that one to the infinite power does not equal one. If
this is true, is there a relatively simple explanation?
 Operations in Nondecimal Bases [10/16/1999]

How can you subtract, multiply, and divide numbers in other bases?
 Ordering Real Numbers [12/11/2000]

Can you describe how to order real numbers?
 The Origin of Lucas Numbers [10/08/1998]

I need help with Lucas Numbers  how and why they were created.
 Paint Formulas in Base 48 [08/20/1998]

I work for a paint store where our formulas are based on an ounce being
48 parts...
 Pairs of Integers [08/16/1997]

Show that there are infinitely many pairs of integers(x,y) such that
xy**2+m and yx**2+m where m is any chosen integer; moreover gcd(x,y)=1.
 Paradox in the Zero Power [09/26/2000]

Why does the product of multiplying a number by itself zero times equal
1?
 Partitioning an Integer [11/14/1998]

How many different ways are there of making a number by adding different
combinations of three numbers?
 Partitions and Products [01/02/2003]

What is the best way of dividing an integer into parts so that the
product of the parts will be as large as possible? Is there a
universal law that tells us what partition will produce the maximum
product for any given number? And can such a law be proved?
 Pascal's Triangle and Fibonacci Formula [02/23/2002]

Prove that the diagonals of Pascal's triangle are the Fibonacci numbers.
 Paths to Triangle Points [05/26/1999]

How can I find the number of paths to a point using Pascal's triangle?
 Pattern in Period [01/31/1999]

Is there any pattern in odd periods with 1 as numerator?
 Patterns in Repeating Decimals [08/06/2003]

Why do certain number sequences repeat in the decimal expansions of
common fractions?
 Patterns in Rolling 3 Dice [09/16/1997]

I have come out with 216 outcomes when rolling 3 dice; while I was
listing all the outcomes, I began to see a pattern...
 Pell Pairs of Positive Integer Solutions [03/29/2012]

Solving a Pell equation confuses a student. Doctor Vogler applies modular arithmetic to
show the way, then concludes with a survey of online resources into Diophantine
equations.
 Percentage of Numbers Divisible by 6, 8 [03/18/2003]

What percentage of numbers is divisible by 6? by 8?
 Percentages of Prime Numbers [01/31/1999]

Does the percentage of prime numbers at every power of 10 decrease until
it reaches a constant value?
 Perfect Logarithms [06/24/2002]

What can you tell me about the equation log(abc)= log(a+b+c)?
 Perfect Number [7/21/1996]

How can I find a perfect number? What are some reference books about
number theory?
 Perfect Number Algorithms [03/31/1998]

What is the formula for a computer program that tests whether an integer
is a perfect integer?
 Perfect Numbers [11/10/1997]

Do the sums of the digits of perfect numbers always equal 1?
 Perfect Numbers [06/15/2002]

Please show that any even perfect number ends in 6 or 8.
 Perfect Square [10/26/2001]

If a and b are positive integers such that (1+ab) divides (a^2+b^2), show
that the integer (a^2+b^2)/(1+ab) must be a perfect square.
 Perfect Square [07/23/2001]

If g.c.d.(x, 3) = 1 and g.c.d.(y, 3) = 1, show that x^2 + y^2 cannot be
a perfect square.
 Perfect Square? [02/18/2002]

If we use the digits 1,2,3,4,5,6,7 each only once to form a 7digit
number, can the resulting number be a perfect square?
 Perfect Square, Cube, Fourth Power [01/25/2002]

Find the least integer greater than 1 that is a perfect square, a perfect
cube, and a perfect fourth power.
 Perfect Square Equation [02/22/2002]

Prove that if n is greater than 1, then nC2 + (n1)C2 is a perfect
square.
 Perfect Squares and Irrational Numbers [02/13/2002]

Isn't any nonperfect square an irrational number? What is the number
0.49? Its square root is 0.7, which is neither irrational nor an integer.
 Perfect Squares: n+125 and n+201 [01/21/2002]

Find the smallest positive integer n so that n+125 and n+201 are both
perfect squares.
 Perfect Squares with Congruences [02/16/2002]

Prove that there is no perfect square a^2 whose last digits are 35.
 Perimeter of Pascal's Triangle [06/05/2001]

Is there a general formula for finding the perimeter of Pascal's triangle
using the number of rows?
 The Phi Function [11/21/1998]

What are the conditions on n,m so that phi(n*m) = phi(n)*phi(m)? What is
phi(p^n*q^m)?
 Polynomial Divisible by 7 [11/14/2001]

Prove that 2^(3n+1) + 4^(3n+1) + 1 is divisible by 7.
 A Polynomial in Three Variables with Few Integer Solutions [03/12/2011]

A student seeks proof that a polynomial in n and two other variables has no integer solutions. After a little insight from modular arithmetic and a lot of searching with a computer algebra system, Doctor Vogler turns up many solutions.
 Positives and Negatives with Infinity and Zero [10/05/1999]

Are there such things in math as +0, 0, and unsigned 0; and +infinity, 
infinity, and unsigned infinity? Are these different?
 Powers of 2 Proof [03/24/2003]

Prove that any number that is not a power of 2 can be expressed as a
sum of two or more consecutive positive integers, but that this is
not possible for powers of 2.
 p, p+8, p+22 Not Prime [10/16/2001]

Prove that there is no positive integer p such that each of the numbers:
p, p+8, p+22 is prime.
 Prefix for 10^30 Bytes [05/25/2000]

What do you call 1,000,000,000,000,000,000,000,000,000,000 or 10^30
bytes?
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