Each of the nine letters represents a different whole number from 1-9. The number in each circle is the sum of the four letters in the squares that meet at that circle.



One of the circles is empty. Can you provide a sum such that there is only one possible set of values for the nine letters?

Computer allowed.

Nice try curly, but you need to find the sum that determines the values of all of the numbers. Your sum is 20, and it can also be solved, for example, as:

258
763
194

5 8 2
7 9 3
1 6 4

That's correct, Denis! All other sums allow more than one way to assign the values.