Determine the correct number to replace the question mark in the figure below.


Solution to the Problem:

The answer is 11

Each pair of horizontally adjacent numbers add up to the square of the number right below them.
4x4=16 (7+9)
7x7=49 (38+11)
9x9=81 (11+70)
11x11=121 (83+38)


Correctly solved by:

1. Morgan Vercimak Mountain View High School
Mountain View, Wyoming
2. Stephanie Graham Mountain View High School
Mountain View, Wyoming
3. Jacquelyn Heltz Mountain View High School
Mountain View, Wyoming
4. JD Pitts Mountain View High School
Mountain View, Wyoming
5. Michelle Johnson Mountain View High School
Mountain View, Wyoming
6. Cherish Register Mountain View High School
Mountain View, Wyoming
7. Les Walker Ventura, California
8. Jeremy Harmon Mountain View High School
Mountain View, Wyoming
9. Philipp Heise ----------
10. Richard K. Johnson La Jolla, California