Digit sum

Usage of digit sum:

The number is divisible by 3, when its digit sum is divisible 3.

The number is divisible by 9, when its digit sum is divisible 9.

Digit sum is the sum of all digits of the integer. We write DS(n).

For example: DS(483) = 4 + 8 + 3 = 15.

How much is DS(831)?

Your answer:

DS(831) = ________.

How much is DS(831)?

Your answer:

DS(831) = 12.