If you are fluent in Italian, it is assumed that you can speak the language well and be able to have conversations with people. If you have just memorized words in Italian, are you fluent? NO! How would you know how to use the word or in what context it is appropriate? What about grammar and the ability to understand when someone asks you a question in Italian?
This holds true with Fact Fluency! The goal shouldn't be to just answer 100 facts in less than 5 minutes. It is understanding what the facts mean and to know how to apply them! Think about a multi-digit multiplication problem....it involves not only multiplication but addition as well! Long division involves division, multiplication and subtraction! When students only memorize their facts, they have a great deal of difficulty with higher order math problems.
Take a look at the slides to see more of an explanation of fact fluency!
Strategies for Doubles. This is the foundation for multiplying by 2's, 4's, 6's and 8's!