Fluency is the ability to use efficient, accurate, and flexible methods for computing something that develops over time; it develops when scholars build from their deep conceptual understanding of each operation combined with number sense. With fluency, scholars are able to confidently compose and decompose numbers using this understanding. Opportunities to determine when to use paper pencil algorithms, mental math, or a computing tool is also a necessary skill and should be provided in problem solving situations.   Efficiency is in the eye of the beholder. What may be efficient for one scholar may not be efficient for all scholars. It is more important that scholars use a method that they understand and provides them accurate results consistently than it is for each scholar to use the same method. Scholars will oftentimes invent their own strategies that make sense to them. These can be built upon to help scholars become fluent in a way that makes sense to them.