1. The number 1232 is divisible by the sum of its digits $1+2+3+2=8$. What is the next number that is divisible by the sum of its digits?
Answer: 1233.

Solution: One can notice that the next number fits, as 1233 is divisible by the sum of its digits $1+2+3+3=9$. Indeed, $1233: 9=137$.

Comment: One could have avoided performing the division and instead used the divisibility rule for 9.