1. Is there a year in the 21st century whose number can be represented as $\frac{a+b \cdot c \cdot d \cdot e}{f+g \cdot h \cdot i \cdot j}$, where $a, b, c, d, e, f, g, h, i, j$ are pairwise distinct digits?
Solution. Yes, for example, $2022=\frac{6+4 \cdot 7 \cdot 8 \cdot 9}{1+0 \cdot 2 \cdot 3 \cdot 5}$. Similarly, 2018, 2020, and 2021 can be represented.