44. Find the sum of all possible different three-digit numbers, all digits of which are odd.
44. Let's write the sum in ascending order of the addends: $111+113+\ldots+$ $+119+131+\ldots+311+313+\ldots+319+\ldots+911+913+\ldots+993+995+$ $+997+999$. The number of addends starting with the digits $1,3,5,7,9$ will be 25 each, so the total number of addends is $25 \cdot 5=125$. The sum of two addends equally distant from the ends is 1110. There are 62 such sums, plus the middle addend is 555, so the desired sum will be $1110 \cdot 62+555=69375$.