Lesson 3.8

For full lesson outline please see Advantage Math Lesson 3.8.

Standards:

4.NBT.5- Use strategies based on place value and the properties of operations to multiply a whole number of up to four digits by a one-digit whole number, and multiply two, two-digit numbers.

Objectives:

Math Objective: Students will be able to draw an open area model to represent two-digit by two-digit multiplication.

Language Objective: Students will work with a partner to discuss how to create an area model along with the appropriate equations.

Vertical Alignment:

3.OA.7.B- Know from memory all products of two one-digit numbers

4.NBT.5- Use strategies based on place value and the properties of operations to multiply a whole number of up to four digits by a one-digit whole number, and multiply two, two-digit numbers.

5.NBT.5- Fluently multiply multi-digit whole numbers using the standard algorithm

Common Misconceptions:

None noted in Advantage Math Lesson 3.8

Lesson Outline:

🚀Launch A(in class or remote)

Students are creating a problem on their own and are representing the problem in an open area model. They may create any problem as long as it is a one-digit X up to four-digit number.
- Questions you could ask:
  - What did you struggle with today that surprised you?
  - Did you get stuck? If yes, where?
- Vocabulary words: No new vocabulary words.

🤔Explore A(in class or remote)

Students are given two problems. Both are solving two-digit X two-digit.
- Questions you could ask:
  - Was one problem more challenging than the other?
  - When adding the partial products, was it difficult to remember to add them all together?
  - Where might someone easily make a mistake in solving?
  - What did you notice about the product of each partial product? (in reference to the 0 at the end of a product when multiplying a number in the 10's place value)

💬Discuss A (in class or remote)

Question to use in your discussion:
- How does the concept of multiplying a number by 10 apply to a number that is larger like 28 or 91?

Additional Resources:

Area Model for Multiplication Two-Digit X Two-Digit: https://learnzillion.com/lesson_plans/6075-use-an-area-model-for-multiplication-of-two-digit-numbers-by-two-digit-numbers/
Anchor Chart for Two-Digit X Two-Digit: https://www.pinterest.com/pin/45458277460323444/

Differentiation (in class or remote)
- Challenge: Have the students make an anchor chart for two-digit x two-digit multiplication to display in the class (see link above).
  - Ways to make remote:
  - Students can do this challenge on their own and submit their work and thoughts.
- Struggling : Have students use the suggestion located in Lesson 3.5 where students who are struggling with writing the distributive property write each section in a box instead of parentheses. This helps students make the connection to the boxes in the array. They can later substitute the rectangles for parentheses.
  - Ways to make remote:
  - Have students join you in an online meeting format (Zoom or Teams) and do the exact same activity. They might not have the place value disks, but you can show them yours to discuss.

Lesson Extension (in class):
- Write the equations within the array, students may want to write just the expression (without solving it) until after they have written the distributive property equation.