Marek is playing with a calculator. He wrote down one number on a piece of paper. He entered it into the calculator and then pressed the buttons in sequence: plus, four, divide, four, minus, four, times, four. He wrote down the result on the paper. Then he repeated the same process with this number, again: plus, four, divide, four, minus, four, times, four. He wrote down the result on the paper again. He repeated the entire process with the newly obtained number and wrote down the result on the paper once more. Then he found that the sum of the four numbers written on the paper is 80. Which numbers and in what order did Marek write down on the paper?

(M. Raabová)
The first number written on the paper is denoted as $x$. Then the second number on the paper has the form:

$$
[(x+4): 4-4] \cdot 4=\left[\frac{1}{4} x+1-4\right] \cdot 4=\left[\frac{1}{4} x-3\right] \cdot 4=x-12 .
$$

This means that each subsequent number written on the paper is 12 less than the preceding number, so the third number will be $(x-24)$ and the fourth $(x-36)$. We get the equation:

$$
\begin{aligned}
x+(x-12)+(x-24)+(x-36) & =80, \\
x & =38 .
\end{aligned}
$$

Marek wrote the following numbers on the paper (in this order): $38 ; 26 ; 14 ; 2$.