Sofya Aleksandrovna Yanovskaya, Russian mathematician of Jewish origin of the 20th century, specialist in logic, posed different problems to her students so that they would solve them with perseverance and so that they would continually ask themselves: ‘What am I doing? Where am I going with this ?’ 

We propose you to solve the following mathematical logic problem.

Place the numbers 1, 2, 3, 4, 5 and 6 in the squares so that each of the circumferences adds up to the same.