## Back Of The Envelope Solution – Design of Computer Programs

[Norvig] And the answer is 20 billion. How do you do that back of the envelope? 5 factorial is 120. Let’s just round that off to 100. 100 to the 5th–that’s 5 times 2–is 10 digits, so that works out to 10 billion. And we rounded down to get from 120 to 100, so we […]