Task 1. Find the sum of all three-digit odd numbers whose product of digits is equal to 140.
Solution. Once the factorization $140=2 \cdot 2 \cdot 5 \cdot 7=4 \cdot 5 \cdot 7$ is performed, it follows that the three-digit numbers are composed of the digits 4, 5, and 7. The odd three-digit numbers composed of these digits are $457, 475, 547$, and 745. Thus, their sum is equal to $457+475+547+745=2224$.