Art of Problem Solving

Complementary counting: Difference between revisions

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"at least"
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'''Complementary counting''' is counting what we don't want, and substracting that from the total number of possibilities. A big hint that complementary counting may lead to a quick solution is the phrase "at least".
'''Complementary counting''' is counting what we don't want, and substracting that from the total number of possibilities. A big hint that complementary counting may lead to a quick solution is the phrase "at least".


== Examples ==
== Examples ==
=== Introductory ===
* [[2006_AMC_10A_Problems/Problem_21 | 2006 AMC 10A Problem 21]]
* [http://www.artofproblemsolving.com/Forum/resources.php?c=182&cid=45&year=2002&p=378321 AIME 2002I/1]


* [http://www.artofproblemsolving.com/Forum/resources.php?c=182&cid=45&year=2002&p=378321 AIME 2002I/1]


=== See also ===
=== See also ===

Revision as of 11:04, 23 July 2006

Complementary counting is counting what we don't want, and substracting that from the total number of possibilities. A big hint that complementary counting may lead to a quick solution is the phrase "at least".


Examples

Introductory


See also