7.2 In a three-digit number, the first digit was crossed out, resulting in a two-digit number. If the original number is divided by this two-digit number, the quotient is 9 and the remainder is 8. Find the original number. (Provide all possible solutions.)
Answer: 4 possible numbers: 224; 449; 674; 899. Hint Let $x$ be the first digit of the original number, and $y$ be the two-digit number after erasing $x$. Then we have the equation $100 x+y=9 y+8 \Leftrightarrow 2 y+2=25 x$. Therefore, $x$ is an even number: $x=2 z$ for some $z$ ( $z \leq 4$ ). Thus, $y+1=25 z$, and the possible values for the number $y+1$ are: $25; 50; 75; 100$, and the corresponding numbers $x$ are $2; 4; 6; 8$.