Calculate Base-k Digit Sum

Calculates base-k digit sum and alternating base-k digit sum of one or more numbers or a whole text. Only numbers are interpreted, all other characters will be ignored. The base-k digit sum is the sum of all k-digit strings, starting from right. For the alternating base-k digit sum, the numbers are alternatingly added and subtracted. String of digits displays the value that is used to get the k-digit sums, which is the text reduced to only its numbers.

Digit number k:

Base-k digit sum:

Alternating base-k digit sum:

String of digits:

Examples:
the base-2 digit sum of 12345 = 45+23+1 = 69
the alternating base-2 digit sum of 12345 = 45-23+1 = 23

If a number is divisible without remainder by 101, then the same is true for its alternating base-2 digit sum and vice versa.