7 Steps to a 7 in Olympiad Combinatorics - Video 3: Looking at Everything

Be sure to follow along with my handout here: https://drive.google.com/file/d/1_Irk... This video is the second of seven videos introducing the most fundamental concepts in Olympiad combinatorics. We introduce the concept of looking at everything at once via double-counting and summation swapping. This idea is often known as the global method. 0:00 - Introduction + Example 4:00 - Counting in two ways 5:39 - Coordinate method example 9:46 - Application of double-counting to problems 12:39 - ARML Example 18:59 - Probabilistic Method Thank you so much for watching this video, please subscribe if you would like to see more videos! #math #olympiad #combinatorics