Task 1. Which of the numbers 723, 732, and 273 will decrease the most and by how much if in each of them the digits 7 and 3 swap places?
Solution. The numbers obtained by such a replacement are

$$
\begin{aligned}
& 732 \rightarrow 372 \\
& 723 \rightarrow 327 \\
& 273 \rightarrow 237
\end{aligned}
$$

and the corresponding differences are

$$
\begin{aligned}
& 732-372=360 \\
& 723-327=396 \\
& 273-237=36
\end{aligned}
$$

According to this, the number 723 will decrease the most, and it will decrease by 396.