Problem:
Three-digit powers of and are used in this cross-number puzzle. What is the only possible digit for the outlined square?
Answer Choices:
A.
B.
C.
D.
E.
Solution:
The -digit powers of are and , so space is filled with a . The only -digit power of beginning with is , so the outlined block is filled with a .
Answer: .
The problems on this page are the property of the MAA's American Mathematics Competitions