Sum of natural numbers equals n+1 choose 2

There is a formula for the sum of the first n natural numbers, which is n(n+1)/2. But that's the same thing as n+1 choose 2! Why are those the same? In this video we give a proof of that connection! Challenge Problems playlist: /playlist/PLug5ZIRrShJGkzGsXMYQt8bi5ImYtiEMM Subscribe to see more new math videos! Music: OcularNebula - The Lopez

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