• 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...
    6 KB (875 words) - 06:50, 10 February 2025
  • 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...
    13 KB (2,523 words) - 07:08, 8 March 2024
  • 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...
    17 KB (2,062 words) - 06:46, 28 January 2025
  • 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...
    18 KB (2,776 words) - 11:20, 10 April 2025
  • 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...
    7 KB (973 words) - 20:41, 13 February 2025
  • 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...
    19 KB (2,632 words) - 12:50, 27 May 2025
  • Thumbnail for Triangular number
    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...
    25 KB (3,600 words) - 20:40, 3 July 2025
  • 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...
    9 KB (984 words) - 00:22, 30 May 2025
  • 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...
    6 KB (943 words) - 22:53, 12 December 2024
  • Thumbnail for Universal Product Code
    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,.....
    50 KB (5,398 words) - 19:13, 1 July 2025
  • 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...
    1 KB (173 words) - 04:42, 20 December 2023
  • 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...
    9 KB (1,095 words) - 05:21, 25 May 2024
  • Thumbnail for ISBN
    ISBN (redirect from 9-digit SBN)
    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...
    62 KB (6,693 words) - 21:11, 27 June 2025
  • Thumbnail for Depreciation
    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...
    28 KB (3,780 words) - 18:43, 22 June 2025
  • 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...
    54 KB (6,801 words) - 17:43, 23 June 2025
  • Thumbnail for Square number
    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...
    18 KB (2,540 words) - 21:45, 22 June 2025
  • 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...
    5 KB (685 words) - 10:15, 31 October 2024
  • 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...
    5 KB (730 words) - 19:47, 12 December 2024
  • Thumbnail for Power of two
    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...
    44 KB (4,372 words) - 19:16, 23 June 2025
  • Thumbnail for Prime number
    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...
    117 KB (14,179 words) - 23:31, 23 June 2025
  • α {\displaystyle \alpha } and β {\displaystyle \beta } have the same digit sum and hence the same remainder modulo b − 1 {\displaystyle b-1} . Therefore...
    17 KB (3,141 words) - 23:18, 12 June 2025
  • Thumbnail for Centered hexagonal number
    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...
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  • Thumbnail for Perfect number
    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...
    38 KB (5,172 words) - 17:00, 3 June 2025
  • Thumbnail for S10 (UPU standard)
    += 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...
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  • {\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...
    10 KB (1,082 words) - 22:07, 2 February 2025
  • Thumbnail for Catalan number
    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...
    40 KB (6,013 words) - 02:24, 6 June 2025
  • Thumbnail for Parity (mathematics)
    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...
    21 KB (2,532 words) - 08:15, 26 June 2025
  • Thumbnail for Hamming weight
    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...
    33 KB (3,163 words) - 07:42, 3 July 2025
  • Thumbnail for Natural number
    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...
    53 KB (5,887 words) - 07:23, 24 June 2025
  • 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...
    4 KB (581 words) - 19:51, 23 April 2025