11. The product of the digits of a three-digit number is 18. The sum of all such three-digit numbers is
Analysis: The key point is the combination of the principle of addition and multiplication with the principle of positional value.
To find the numbers that meet the conditions, we first need to identify which digits form such three-digit numbers, and then form such numbers. $18=1 \times 2 \times 9=1 \times 3 \times 6=2 \times 3 \times 3, 1, 2, 9$ can form $129,192,219,291,912,921$, their sum is $2 \times(1+2+9) \times 111$, the sum of the other two groups is $2 \times(1+3+6) \times 111, (2+3+3) \times 111$, so the total sum is $111 \times 52=5772$