Math Quiz: NYT Learning Network

Through Math for America, I am part of an on-going collaboration with the New York Times Learning Network.  My latest contribution, a Test Yourself quiz-question, can be found here:

https://learning.blogs.nytimes.com/2011/10/03/test-yourself-math-oct-3-2011/

This question is based on Facebook’s claim that they have 800 million users, and asks “What percentage of the world’s population uses Facebook every day?”