Summing it up
FEW TASKS SEND SHIVERS up more spines than a math problem. Expunge your fears by cracking these puzzles (instructions below; answers on page 124) dubbed “Sums” by their creator, engineer Gordon Burgin.
A small set of rules:
The numbers in each sector of the above circle, square, and star equal the sum of the numbers in the circles that border them. Easy enough, right? A few more caveats: The numbers in the small circles can be only 0 through 9, and each digit can appear only once. (The most common solution is listed on page 124, but other solutions might exist.)