What is a digit sum of a number?

Answer 1

To find the digit sum of a number you plus the first 2 numbers together, example:

the number 18, 18 is made up of 2 digits 1 and 8.

If you add the 2 digits together you get a total of 9.

So that is the digit sum of 18.

But if you use a higher number like 66 then the method has a small change.

First if you add the two digits together it becomes 12.

But 12 isn't a single digit sum.

So again the 2 digits have to be added together to make a single digit sum.

1+2=3 so 3 is the single digit sum for the number 66.