Question 15
A positive integer with at most nine digits is good if its units digit is $0$ or $1$, tens digit $0,1,2$, hundreds digit $0,1,2,3$, thousands digit $0,1,2,3,4$, and so on. The first ten are $1,10,11,20,21,100,101,110,111,120$. What is the hundredth good number?