Number Theory
Math and statistics calculators with step-by-step formulas and worked examples for students and professionals.
GCF and LCM Calculator
Find the greatest common factor (GCF) and least common multiple (LCM) of two or more numbers, with the prime factorization of the GCF shown.
Factorial Calculator
Calculate n factorial (n!) exactly for n up to 18, or in scientific notation for n up to 170, plus trailing zero count and natural log of n!.
Permutation and Combination Calculator
Calculate permutations (nPr) and combinations (nCr) of n items taken r at a time, with and without repetition. Free calculator with clear examples.
Modulo Calculator
Calculate a mod b with both the floored (mathematical) and truncated (programming) sign conventions, plus the quotient and division equation.
Digital Root Calculator
Find the digital root of any whole number by repeatedly summing its digits until a single digit remains. Shows each step and the connection to mod 9.
Fibonacci Sequence Calculator
Find the nth Fibonacci number, the sum of the first n terms, and how the ratio of consecutive terms approaches the golden ratio. Free and instant.
Prime Factorization Calculator
Break any whole number down into its prime factors, with exponent notation, number of divisors and sum of divisors. Free and instant, up to 1 trillion.
Bitwise Operations Calculator
Perform bitwise AND, OR, XOR, NOT, left shift and right shift on two 32-bit integers. See binary representations and results instantly.