11. (12 points) Fill in the blanks with numbers $1-5$, so that the numbers in each row and each column are not repeated, and each division operation from top to bottom or from left to right can be performed without a remainder. Then the three-digit number formed by the first three numbers in the second row is $\qquad$ .


【Answer】Solution: First, according to the known number 5, the number below it cannot be even and can only be 3, so the number above 5 can only be 1.

Then, according to the number 3 in the third row, it can only be paired with 1, so the front is $4 \div 2$ and the back is 3 divided by 1.
Then, according to the number pattern in the first row, the last number can only be 3, i.e., $42 \div 3$.
Continuing the reasoning, we get:
Therefore, the answer is: 531