## Task 7 - V00907

The sum of the digits of a two-digit number is 12. If you subtract from this number the number that contains the same digits in reverse order, you get 54. What is the number?
Let the sought number $z$ be $z=10a+b$. Then for the digits $a$ and $b$

\[
\begin{aligned}
a+5 & =12 \\
(10a+5)-(10b+a) & =54
\end{aligned}
\]

The system of equations has the solution $a=9$ and $b=3$. Since $93-39=54$ the check is correct, so 93 is the sought number.