Description: Explanations and examples of how the Standards for Mathematical Practice apply to Grades K-5. Look for and express regularity in repeated reasoning. Mathematically proficient students notice if calculations are repeated, and look both for general methods and for shortcuts. Students might then express this regularity by saying something like, "When you change one factor by 1, the product increases by the other factor." Mathematically proficient elementary students formulate conjectures about what they notice, for example, that when 1 is added to a factor, the product increases by the other factor; or that, whenever they toss counters, for each combination that comes up, its "opposite" can also come up.