I am sure your second grader knows what "add" means and "equals" but can they define the math meaning of "difference"? How about "faces" and do they remember "unit" and "combinations" from first grade? With the Common Core State Standards communicating about mathematical thinking is very important and to do so we need a good grasp on math vocabulary. Additionally, besides being able to write and speak math terms like angles and sum, students need to be able to independently read and understand written math directions on their own. In a testing situation, teachers may be able to read what a word says but if a student does not remember it they will not be able to define it (of course in everyday lessons and not on tests, yes we would help). For example, "Write a subtraction equation in which the difference is 6" or "Write a number model in which the sum is 8" would require not only computation but knowing w...