Joining Numbers

If we have 2 numbers $\overline { abc }$ and $\overline { def }$ we can join this 2 number to make other more large $\overline { abcdef }$ . If we join more one number $\overline { ghi}$ we have $\overline { abcdefghi }$ .

We can reduce a number summing their digits to get only a 1-digit number: $362 \Rightarrow 3+6+2=11 \Rightarrow 1+1=2$ . If we reduce the number 362 we get 2.

If we join all 3-digit numbers multiples of 9 to make a other more large, and reduce this number, we get a number $n$ . What is the value of $\frac {n}{3}$ ?