See also the
Dr. Math FAQ:
0.9999 = 1
0 to 0 power
n to 0 power
0! = 1
dividing by 0
Browse High School Number Theory
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Selected answers to common questions:
Infinite number of primes?
Testing for primality.
What is 'mod'?
- Conjecture About Squares of Consecutive Numbers [08/28/2001]
When any two rational numbers whose absolute values are 1 apart are
squared, the difference of the squares is equal to the absolute value of
- Conjectures vs. Hypotheses [01/12/1999]
What is the difference between the terms 'conjecture' and 'hypothesis'?
Should the Riemann hypothesis be the Riemann conjecture?
- Connecting the Dots [03/14/1999]
If you have a few dots on a page, how many lines does it take to connect
them all to each other?
- Consecutive Composite Numbers [07/05/2002]
Find 1000 consecutive composite numbers.
- Consecutive Composite Numbers [06/07/2005]
Is it possible to find m consecutive composite numbers where m is any
- Consecutive Fibonacci Numbers Relatively Prime [11/17/2001]
Prove two consecutive Fibonacci numbers are relatively prime.
- Consecutive Integers [02/10/1999]
Can the product of four consecutive integers be a perfect square?
- Consecutive Integers, Divisible by the Sums of Their Digits [05/20/2002]
Find the first three consecutive integers greater than 10, each of
which is divisible by the sum of its digits.
- Consecutive Non-Prime Integers [2/17/1996]
For any integer n > 1 there exist n consecutive non prime integers. I
have taken n = 4 and then used 24,25,26,27 as a specific example.
However, for n large I don't see how this can hold.
- Continued Fraction for Tan(x) [11/03/2000]
Can you tell me why the "infinite continued fraction representation" for
the tangent function works?
- Continued Fractions [10/07/1997]
Exactly what are "continued fractions"?
- Convergence of a Prime Sequence [02/10/2002]
We know the sum(1/n) (n=1, infinity) does not converge, but what about
sum(1/p) where sum is over prime numbers only. Does it converge?
- Converting a Base 2 Log [01/31/2002]
2147483647 is one less than what power of 2?
- Converting a Fraction Into a Continued Fraction [11/29/2003]
I know how to convert a continued fraction into a standard fraction,
but I can't figure out how to to the other way. How can I convert a
standard fraction into a continued one?
- Converting any Number Base to Another [05/11/2001]
Is there a particular technique for the conversion of any number base
into any other base? I also need information on basic numeric
calculations within a base 5 system.
- Converting Base Numbers Directly Without Using Base 10 [01/26/2004]
How do you convert from one base to another without going through base
10? How do I go from base 3 to base 7, for instance? Would the same
algorithm work to go from base 5 to base 12?
- Converting Bases [9/5/1996]
How do I convert from one base to another - i.e. decimal to bin, hex, and
- Converting Bases [12/21/1997]
How do you convert hexadecimal, binary, and decimal numbers?
- Converting Bases Without Going through Base 10 [09/04/2002]
Is there a way to convert between bases without going through base 10?
- Converting Binary and Decimal to Hexadecimal and Back [08/12/2001]
How do you convert binary and decimal numbers to hexadecimal and vice
- Converting Binary to and From Decimal [06/16/1999]
Can you show me how to convert base 2 numbers into base 10 and vice-
- Converting Decimal Numbers from Base 2 to Base 8 or 16 [02/20/2009]
I understand converting binary to octal or hexadecimal in general, but
am curious how you handle the decimal portion of a number.
- Converting Directly from Base to Base [04/01/2001]
Is there a way of reducing the representation of a natural number from
one base to another directly without reducing to base 10 first?
- Converting Floating Decimals to Other Bases [11/27/2003]
I know how to convert integers to other bases. But how do I convert
the decimal parts of non-integers such as 123.5 or 8.4444....?
- Converting Fractions from Binary to Decimal [02/25/2002]
Can you explain how to convert binary fractions to decimal numbers, e.g.
- Converting from Base 10 to Base 3 [02/12/2002]
How do you convert a base 10 number (example 2315) to base 3?
- Converting from One Base to Another [10/28/1996]
How do you convert a number base 9 to base 4? from base 9 to base 10?
- Converting Negative Decimals to Hexadecimal [05/30/2001]
Using a calculator I can get conversions like - 16 = F0, but what I need
to know is how to get to F0 from - .16
- Converting Numbers: Binary to Decimal [11/20/1997]
I just cannot convert from binary to decimal and back again.
- Converting Repeating Decimals from Base X to Base Y [10/02/2009]
How do I convert a repeating decimal from base 9 to base 6? For
example, 0.54444444... (base 9) to base 6.
- Converting to Base 16; Place Value Chart [03/22/1998]
How do you convert numbers to base 16 numbers?
- Converting to Binary [05/27/2001]
Converting the number .78125 to its binary equivalent.
- Coprimes in Fermat's Last Theorem [06/03/1999]
Why are (z-x)/2 and (z+x)/2 coprime in Fermat's Conjecture when n = 2?
- Countability of Rational and Irrational Numbers [01/30/2001]
When speaking of countability of numbers, which has more, rational or
- Counting Digits [03/13/2002]
How many times does each digit appear when counting from 1-1000 and 1-
10000 (including zeros)?
- Counting Even Digits in Three-Digit Numbers [10/24/2004]
How many 3-digit numbers are there in which the number of even digits
- Counting in Base 5 [03/02/2004]
How do I count from 1 to 7 in base 5?
- Counting Odd Coefficients [05/27/1998]
If (1+x)^100 is multiplied out, how many of the coefficients are odd? How
would you generalize?
- Counting Positive Rational Numbers [09/09/2001]
In Hardy's book _Pure Mathematics_ he gives a formula for counting the
positive rational numbers p/q when they are arranged in a triangular
matrix and counted down diagonally from the top row... how can it be
proved for all such numbers?
- C++ Program to Convert Decimal to Binary [10/26/1999]
Can you show me a C++ routine that converts decimal numbers to binary?