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 (881 words) - 17:07, 27 February 2024
Digital root (redirect from Repeated digital sum)
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
Casting out nines (section Digit sums)
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 (2,059 words) - 15:25, 22 May 2024
Harshad number (section Sums of harshad numbers)
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 (2,596 words) - 00:26, 19 June 2024
last digit. With the payload, start from the rightmost digit. Moving left, double the value of every second digit (including the rightmost digit). Sum the...
9 KB (967 words) - 17:55, 14 October 2024
Cube (algebra) (section Sum of first n cubes)
last two digits. Except for cubes divisible by 5, where only 25, 75 and 00 can be the last two digits, any pair of digits with the last digit odd can occur...
24 KB (3,006 words) - 05:25, 7 September 2024
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 (6,861 words) - 21:17, 4 September 2024
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
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...
17 KB (2,534 words) - 23:50, 11 August 2024
Palindromic number (section Sum of the reciprocals)
where it is written in standard notation with k+1 digits ai as: n = ∑ i = 0 k a i b i {\displaystyle n=\sum _{i=0}^{k}a_{i}b^{i}} with, as usual, 0 ≤ ai < b...
18 KB (1,963 words) - 11:58, 21 October 2024