In each of the two boards below, put each of the counters numbered 1, 2, 3, 4, 5 and 6 into a different circle. You score 1 point for a circle if the number printed next to the circle is equal to the sum of the numbers on the counters in all neighbouring circle. (Circles are neighbours if they are connected by a line.) The object is to get as high a total score as possible.
Based on a puzzle in Paul Vaderlind's The Inquisitive Problem Solver.