In mathematics, the digit sum of a natural number in a given number base is the sum of all its digits. For example, the digit sum of the decimal number...

repeated digital sum) of a natural number in a given radix is the (single digit) value obtained by an iterative process of summing digits, on each iteration...

procedures: Adding the decimal digits of a positive whole number, while optionally ignoring any 9s or digits which sum to 9 or a multiple of 9. The result...

number) in a given number base is an integer that is divisible by the sum of its digits when written in that base. Harshad numbers in base n are also known...

A sum-product number in a given number base b {\displaystyle b} is a natural number that is equal to the product of the sum of its digits and the product...

visually demonstrated in the following sum, which represents T 4 + T 5 = 5 2 {\displaystyle T_{4}+T_{5}=5^{2}} as digit sums: 4 3 2 1 + 1 2 3 4 5 5 5 5 5 5 {\displaystyle...

A very simple check digit method would be to take the sum of all digits (digital sum) modulo 10. This would catch any single-digit error, as such an error...

digit, starting from the last digit. If doubling a digit results in a value > 9, subtract 9 from it (or sum its digits). Sum all the resulting digits...

equation, then it is not a valid UPC-A. The UPC-A check digit may be calculated as follows: Sum the digits at odd-numbered positions (first, third, fifth,.....

mathematics, the Digit-reassembly numbers, or Osiris numbers, are numbers that are equal to the sum of permutations of sub-samples of their own digits (compare...

digital sum: The digit sum - add the digits of the representation of a number in a given base. For example, considering 84001 in base 10 the digit sum would...

number in a given number base b {\displaystyle b} that is equal to the sum of its digits each raised to the power of itself. An example in base 10 is 3435...

check digit (which is the last digit of the 10-digit ISBN) must range from 0 to 10 (the symbol 'X' is used for 10), and must be such that the sum of the...

years' digits. Since the asset has a useful life of 5 years, the years' digits are: 5, 4, 3, 2, and 1. Next, calculate the sum of the digits: 5+4+3+2+1=15...

the sum of its digits is divisible by 3 (or 9). Adding the digits of a number up, and then repeating the process with the result until only one digit remains...

an even digit followed by a 1; if the last digit of a number is 2 or 8, its square ends in an even digit followed by a 4; if the last digit of a number...

the number by the sum or product of its digits until one reaches a single digit. Because the numbers are broken down into their digits, the additive or...

million digits. The Electronic Frontier Foundation also offers $150,000 and $250,000 for primes with at least 100 million digits and 1 billion digits, respectively...

natural number with an even number of digits, that can be factored into two natural numbers each with half as many digits as the original number, where the...

sum of all n-choose binomial coefficients is equal to 2n. Consider the set of all n-digit binary integers. Its cardinality is 2n. It is also the sums...

rightmost (least significant) digits follow the pattern 1–7–9–7–1 (repeating with period 5). This follows from the last digit of the triangle numbers (sequence...

number theory, a perfect number is a positive integer that is equal to the sum of its positive proper divisors, that is, divisors excluding the number itself...

+= weights[i] * int(digit) sum = 11 - (sum % 11) if sum == 10: sum = 0 elif sum == 11: sum = 5 return sum function getCheckDigit(num) { const weights...

odd if its last digit is 1; and it is even if its last digit is 0. In an odd base, the number is even according to the sum of its digits—it is even if and...

an odd prime, count all digits greater than (p + 1) / 2; also count digits equal to (p + 1) / 2 unless final; and count digits equal to (p − 1) / 2 if...

{\displaystyle b} is a number that is the sum of its own digits each raised to the power of the number of digits. Let n {\displaystyle n} be a natural number...

case, a given set of bits, this is the number of bits set to 1, or the digit sum of the binary representation of a given number and the ℓ₁ norm of a bit...

α {\displaystyle \alpha } and β {\displaystyle \beta } have the same digit sum and hence the same remainder modulo b − 1 {\displaystyle b-1} . Therefore...

use of a 0 digit in place-value notation (within other numbers) dates back as early as 700 BCE by the Babylonians, who omitted such a digit when it would...

number that cannot be written as the sum of any other natural number n {\displaystyle n} and the individual digits of n {\displaystyle n} . 20 is a self...