Description: The work of Topic A transitions naturally into Topic B; students employ concrete and pictorial representations of the vertical algorithm when they encounter addition problems for which there is no clear simplifying strategy. In Lessons 8 and 9, students continue to build their conceptual understanding as they relate manipulatives to the algorithm, recording compositions as new groups below in vertical form as they did in Module 4. In Lessons 10 and 11, students move from concrete to pictorial representations as they draw chip models to represent addition within 1,000. In Lesson 12, students are presented with a variety of problems for which they must choose an appropriate strategy to solve.*Teacher Advisor is 100% free.