Problem:
The ten-letter code  represents the ten digits , in order. What -digit number is represented by the code word 
Answer Choices:
A.  
B.  
C.  
D.  
E.  
Solution:
Because the key to the code starts with zero, all the letters represent numbers that are one less than their position. Using the key, is , and similarly is is , and is .
Answer: .
The problems on this page are the property of the MAA's American Mathematics Competitions