Petr glued 17 dice into a snake (as shown in the picture). He always glued the sides with the same number of dots. Then he examined the snake from all sides and correctly calculated the total number of dots on its surface. What did he get? (The sum of the dots on opposite sides of a die is 7.)

(S. Bodláková, M. Dillingerová)

![](https://cdn.mathpix.com/cropped/2024_04_17_a36e361d6d455c7cf0e3g-2.jpg?height=203&width=717&top_left_y=2023&top_left_x=698)
Given that the sum of the dots on opposite sides of a die is always 7, we have a total of $17 \cdot 2$ such pairs on the "long" side of the snake and one pair on the sides. In total, we therefore have 35 pairs. Therefore, Petr must have counted $35 \cdot 7=245$ dots.