Strategies for Multiplying by 2-,3-, and 4-Digit Whole Numbers – Part 1

1. Strategies for Multiplying by 2-,3-, and 4-Digit Whole Numbers – Part 1 Unit of Study: Strategies and Properties of Multi-Digit Multiplication Global Concept Guide: 2 of 3

2. Content Development • “Drawing diagrams is a valuable tool for students and has the benefits of helping them organize their information, visualize the relationship of the information, and develop a mental image they can utilize to solve. The model then needs to illustrate and lead to the connection of the Distributive Property.” - GoMath! • Teachers should ask questions that lead students to make the discovery that if they break apart their factors into expanded form when using partial products, they can use the multiplication patterns to help them solve for their solution. • As students become more efficient in the strategy they can be encouraged to break apart their factors in different ways, rather than just using place value. • Students should estimate before they find the exact answer so they are able to check for the reasonableness of their solution. • *Note this GCG is similar to Unit 6, GCG 1 - just with larger numbers.

3. Day 1-2 • Essential Question: How can your understanding of using models for multiplication by 1-digit numbers help you when multiplying by larger numbers? • By the end of day 2, students should be able to model multiplication problems and record them numerically. Make sure students are using base ten language throughout the process. • Students should be exposed to various problems that are: 2 digit by 2 digit, 2 digit by 3 digit, 2 digit by 4 digit, 3 digit by 3 digit. *Note based on the item specifications students are not assessed in 4th grade on 3 digit by 4 digit multiplication problems.

4. Day 3 • Essential Question: How can you use partial products/distributive property when multiplying by multi-digit numbers? • By the end of day 3, students will move from creating models of partial products to the numerical decomposition of multi-digit multiplication problems in order to solve. • *Note that some students struggling with the transition may still need to go back and make partial products boxes to solve.

5. Day 4Enrich/Reteach/Intervention • Essential Question: How can you use partial products/distributive property when multiplying by multi-digit numbers? • Reteach – Use centimeter grid paper for smaller 2 digit by 2 digit multiplication problems to model the breaking apart into tens and ones. Then transition to the partial products box model, making connections between the two strategies. Good resources to use include!Go Math Reteach Activity TE p.205B, and Reteach Activity TE p.219B. • Core – Students should be using the partial products algorithm, both box and numerically, to solve selected story problems from Go Math. They should be able to use both strategies flexibly. Possible game option: students roll a dice – if the roll is even they solve with partial products box model, if the roll is odd they solve with partial products algorithm (numerically). • Enrich – Students are breaking apart the multi-digit numbers in different ways in order to solve for the multiplication problem. Good resources to use include: E43, E45, E46, E47.