Minilessons for Extending Addition and Subtraction is one of three yearlong resource guides in Contexts for Learning Mathematics’ Investigating Number Sense, Addition, and Subtraction (K–3)
Minilessons for Extending Addition and Subtraction can be helpful in grades 2–3 as you work with addition and subtraction beyond the basic facts. These minilessons are crafted with computation problems that, when placed together, are likely to generate discussion of certain strategies or big ideas that are landmarks on the landscape of learning for addition and subtraction, particularly with two and three digits. The guide contains approximately 75 minilessons, structured as strings of related problems.
Although the emphasis is on the development of mental arithmetic strategies, this does not mean learners have to solve the problems in their heads—but it is important for them to do the problem with their heads! In other words, as you use this guide, encourage students to examine the numbers in each problem and think about clever, efficient ways to solve it. The relationships between the problems in the minilesson will support them in doing this. The open number line is used throughout to represent student strategies.