This great brain-teasing *math* challenge is created for those who enjoy solving complicated logic problems. The solution is also given.

## Challenge:

The numbers in each set of nine numbers are related in a certain way. What is the value of the question mark?

### The Absolute Best Book** to ****challenge your Smart Student!**

The correct answer is 1.

Column 3 on right is the sum of two columns of the right set minus the difference of the two right columns of the left set of numbers.