The Common Core State Standards present a helpful taxonomy for understanding the various types of addition and subtraction word problems. Considering these many contexts, and the fact that any number in a situation may be unknown in any given situation, there are so many possible variations in these word problems! To help students be able to eventually approach and solve any addition or subtraction situation, it is important to help students develop the habits of mind and approaches necessary to make sense of word problems in general. This curriculum unit, written at Yale University in Summer 2015, uses a modeling method to help students make sense of word problems, and presents a logical sequence of presenting students with one-step and two-step problems. The unit also describes how to use a structured problem-solving lesson format to drive student higher-order thinking.

This curriculum unit will be taught to 3^rd grade students but can be modified for 2^nd grade and 4^th grade classrooms. The research presented on word problem types, modeling, and structured problem solving is useful professional development for math teachers at all grade levels.

(Developed for Mathematics, grade 3; recommended for Mathematics, grades 2-4)