Sofia places the dice on a table as shown in the figure
Source: May Olympiad 2020 L1 P1
March 14, 2021
combinatorics
Problem Statement
Sofia places the dice on a table as shown in the figure, matching faces that have the same number on each die. She circles the table without touching the dice. What is the sum of the numbers of all the faces that she cannot see?
. In all given the numbers on the opposite faces add up to 7.