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 TOPICS This page:   number theory    Search   Dr. Math See also the Dr. Math FAQ:   0.9999 = 1   0 to 0 power   n to 0 power   0! = 1   dividing by 0   number bases Internet Library:   number theory HIGH SCHOOL About Math Analysis Algebra    basic algebra    equations/graphs/      translations    linear algebra    linear equations    polynomials Calculus Complex Numbers Calculators/    Computers Definitions Discrete Math    permutations/    combinations Exponents    Logarithms Fibonacci Sequence/   Golden Ratio Fractals Functions Geometry    Euclidean/plane      conic sections/        circles      constructions      coordinate plane      triangles/polygons    higher-dimensional      polyhedra    non-Euclidean    practical geometry    symmetry/tessellations History/Biography Interest Logic Negative Numbers Number Theory Physics/Chemistry Probability Projects Puzzles Sequences/Series Sets Square/Cube Roots Statistics Transcendental   Numbers Trigonometry 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'? Finding Formulas for Number Sequences [11/22/1997] My question is about trying to find a formula between numbers. Finding Howlers [10/25/1999] Howlers are fractions like 16/64; when you cross out the 6 on the top and the bottom, you are left with 1/4, which is the simplified fraction. How can I find all 2-digit, 3-digit and 4-digit howlers? Finding Integer Pairs Whose Product Consists Only of 1's and 0's [10/06/2004] Given the base-10 representation of any integer a, does there exist a non-zero integer b such that the base-10 representation of the product ab contains only ones and zeros? Finding Integer Solutions to a^b = b^a [02/02/2005] Find all positive integers a and b such that a^b = b^a, and prove that you have found them all. Finding Mersenne Primes [02/15/2002] How do I find the first four Mersenne primes? Finding N Consecutive Composite Numbers [02/26/2001] How can I find N-1 consecutive numbers that are not prime for any number N greater than 1? Finding Number of Trailing Zeros in Factorials [01/27/2005] I noticed a way to compute the number of trailing zeros of a factorial in base 10 or 6 at your site. But that method doesn't seem to work for me in bases such as 4, 8, and 16. Finding Patterns in Digits [04/29/1998] How can we find other solutions to problems like 2^5*9^2 = 2592? Finding Perfect Cube Factors of 10! [04/12/2005] To find all perfect cubes that are factors of 10!, you don't need to actually evaluate 10!. Finding Pi [11/14/1997] What is the quickest algorithm for finding pi? Finding Prime Factors of Factorials [11/26/2004] How many factors of 2 are contained in 100! ? Finding Prime Numbers [11/10/1997] What is the fastest way to determine if a number is prime? Finding Products of a Range of Numbers [03/28/2002] What method or formula is there to solve for the product of a range of numbers? Finding Pythagorean Triplets [02/02/2006] Without using the standard a = n^2 - m^2, b = 2nm, c = n^2 + m^2, how can you work out Pythagorean triplets? For example, how could you find triplets where the hypotenuse exceeds one leg by a certain amount? Finding Pythagorean Triplets Algebraically [04/13/2002] Is there a way to find Pythagorean triplets of Type I algebraically? Finding Sets of 7 Prime Numbers That Sum to 100 [05/22/2007] There are 35 different sets of 7 prime numbers that sum to 100. Of those sets, which has the largest product, and which has the largest number? I'm using trial and error and it's very frustrating. Is there a better way? Finding Sets of Integers [01/02/2002] Without computer assistance, find five different sets of three positive integers such that and k is less than and m is less than n, and 1/k + 1/n + 1/m = 19/84. Finding the Exponent with a Modulus [05/24/2003] I am trying to work out k in the following question: 23^k = 201545 (mod 900001). Finding the Last Digits of a Large Exponential [01/01/2005] What are the last five digits of 7777777^7777777? Finding the Sum of the Factors of a Number [07/25/2007] Is there a formula to find the sum of all the factors of a given number? Finding the Two Squares [06/11/2003] One of Fermat's theorems says that every prime number that yields a remainder of 1 when divided by 4 can be expressed as the sum of two integer squares (e.g.: 97 = 4^2 + 9^2). This theorem was proven by Fermat. What methods are known for determining the two squares? Find Number Given Divisor and Remainder Information [01/21/2009] A four digit number N leaves remainder 10 when divided by 21, remainder 11 when divided by 23 and remainder 12 when divided by 25. What is the sum of the digits of N? Find Remainders: 3^2002/26, 5^2002/26 [09/21/2002] Find the remainders obtained when 3^2002 and 5^2002 are divided by 26; show that 3^2002 + 5^2002 is divisible by 26. Find the Flaw [08/02/2001] I don't understand where the following proof goes wrong... Find the Monster Mod 11, Mod 2310 [05/07/2003] Find an integer n between 0 and 2309 with the property that 10^10^10^ 34 = n (mod 2310). Find the Smallest Number... [10/21/1997] ... that has factors of 1, 2, 3, 4, 5, 6, 7, and 8. Find the Smallest Number - A Remainder Problem [09/27/2001] Find the smallest number, M, such that: M/10 leaves a remainder of 9; M/9 leaves a remainder of 8; M/8 leaves 7; M/7 leaves 6; M/6 leaves 5; M/5 leaves 4; M/4 leaves 3; M/3 leaves 2; and M/2 leaves 1. Find the Smallest Triangle [05/25/2001] A triangle has sides whose lengths are consecutive integers. Its area is a multiple of 20. Find the smallest triangle that satisfies these conditions. Find the Solution: r^2 + s^2 = c. [01/28/2003] Given c, find a^2 + b^2 = c^2. Find the Unknown Base [06/25/2003] Two numbers are multiplied to equal another number, which generates a false number statement. What base is it? Finite Series and Greatest Integers [03/06/2003] For n a positive integer, let t(n) denote the number of positive divisors of n (including n and 1), and let s(n) denote the sum of these divisors. Prove the following:... Finite vs. Infinite [07/10/1997] If a line segment is a measurable part of a line, why is the number of points that make up a line segment infinite? Finite vs. Rational [9/10/1996] A right triangle with sides 1 and 2 has a hypotenuse equal to the square root of 5, which is irrational - it carries on to infinity without recurring - but the side length of a triangle must be finite! First Calculation of E [12/18/1997] How did Euler first calculate the value of e? The 'First to 100' Game [03/12/2001] Two players take turns choosing any number from 1-10, keeping a running sum of all the numbers. The first player to make this sum exactly 100 is the winner. Is there a surefire way to win this game? Fixed Point and Floating Point Numbers [05/19/2000] What are fixed point or fixed decimal numbers? How do they differ from floating point numbers? Floating 2 [06/12/2001] Start with the number 2 on the far left side, then float the number 2 to the far right side; the new number must be three as large as the old number. Floating-Point Binary Fractions [07/19/1999] How can you represent fractions such as 12.93 in binary? How do computers represent such numbers? Floor and Ceiling [05/28/2000] What do 'floor' and 'ceiling' mean in mathematics? Forming Palindromic Numbers [12/04/1998] Can you give me some examples of forming palindromic numbers with different operations? How many steps would it take? Page: [] [last>>]

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