Problem 3. The digit in the hundreds place of a given three-digit number is 7. If we move this digit to the units place, the digit in the tens place to the hundreds place, and the digit in the units place to the tens place, we will get a new three-digit number which is 567 less than the given number. Find the given number.
Solution. Let the original number be the number $\overline{7 x y}$, where $x$ and $y$ are digits. From the condition of the problem, we get

$$
\overline{7 x y}=567+\overline{x y 7} \text {, i.e. } 700+\overline{x y}=567+10 \overline{x y}+7
$$

from which we find $9 \overline{x y}=126$, i.e. $\overline{x y}=14$. Finally, the desired number is 714.