If I take any natural number, add the digits together until they produce a one digit number, like in the following example $5847\ \ \rightarrow\ \ 5+8+4+7=24\ \ \rightarrow\ \ 2+4=6$ which single digit number $n$ to end up with is the most common?
If the answer depends on the maximum natural number $N$, then what is the most probable $n(N)$?