Unit 4, Lesson 13# Use math drawings to represent subtraction with and without decomposition and relate drawings to a written method

EngageNY 60 min(s)

In this lesson, students deepen their understanding of subtraction by understanding the relationship between their drawings and the subtraction algorithm. They use a more abstract chip model, in which place-value disks are replaced by circles or dots to model the subtraction of two-digit numbers. Students record each change they make to their model while simultaneously using the algorithm.