Casework

Casework is a counting approach that breaks a problem into two or more subproblems (the cases) and adding the result from each case together. While casework is sometimes the most elegant method of solution, it may be considered brute force when a more elegant solution exists.

Videos

• Casework,Complementary Counting,and OverCounting(PIE) by Sohil Rathi
• AoPS Casework Counting Part 1
• AoPS Casework Counting Part 2

Example Problems and Solutions

Introductory

• 2006 AMC 12A Problem 20

• 2005 AMC 10A Problem 14

Intermediate

• 2004 AIME 2 Problem 2
• 2004 AIME 2 Problem 4
• 2005 AIME 1 Problem 5
• 2000 AIME 1 Problem 5

See also

• Math books