﻿ Grade 3 Mathematics Module 3, Topic B, Overview | EngageNY

## Grade 3 Mathematics Module 3, Topic B, Overview

Topic B introduces units of 6 and 7, factors that are well suited to Level 2 skip-counting strategies and to the Level 3 distributive property strategy, already familiar from Module 1.  Students learn to compose up to, then over the next decade.  For example, to solve a fact using units of 7 they might count 7, 14, and then mentally add 14 + 6 + 1 to make 21.  This strategy previews the associative property using addition and illuminates arithmetic patterns as students apply count-bys to solve problems (3.OA.9).  In the next lesson, students apply the distributive property (familiar from Module 1) as a strategy to multiply and divide.  They decompose larger unknown facts into smaller known facts to solve.  For example, 48 ÷ 6 becomes (30 ÷ 6) + (18 ÷ 6), or 5 + 3 (3.OA.5, 3.OA.7).  Topic B’s final lesson emphasizes word problems, providing opportunities to analyze and model.  Students apply the skill of using a letter to represent the unknown in various positions within multiplication and division problems (3.OA.3, 3.OA.4, 3.OA.7).