Problem:
What is the difference between the sum of the first  even counting numbers and the sum of the first  odd counting numbers?
Answer Choices:
A.  
B.  
C.  
D.  
E.  
Solution:
Each even counting number, beginning with , is one more than the preceding odd counting number. Therefore the difference is .
Answer: .
The problems on this page are the property of the MAA's American Mathematics Competitions