Lesson 8

Multiply 2 Two-digit Numbers

Lesson Purpose

The purpose of this lesson is for students to multiply 2 two-digit numbers.

Lesson Narrative

Previously, students used place-value reasoning to decompose a factor in a multiplication expression to multiply numbers up to four-digit by one-digit numbers. In this lesson, they apply these ideas to multiply 2 two-digit numbers. They reason about why it is helpful to decompose both two-digit numbers by place value. As students analyze the connections between expressions and diagrams, they recognize that partial products in which the factors are either single-digit numbers or multiples of 10 can be found mentally, making the rectangular diagram a useful tool for multiplying two-digit numbers.

• Action and Expression
• MLR8

Learning Goals

Teacher Facing

• Multiply 2 two-digit numbers using place value understanding and properties of operations.

Student Facing

• Let’s multiply 2 two-digit numbers.

Lesson Timeline

 Warm-up 10 min Activity 1 20 min Activity 2 15 min Lesson Synthesis 10 min Cool-down 5 min

Teacher Reflection Questions

In a future lesson, students will be analyzing partial products from rectangular diagrams and making connections to the traditional algorithm notation. How do rectangular diagrams support this thinking?

Suggested Centers

• Number Puzzles: Multiplication and Division (4–5), Stage 1: Two-digit Factors (Addressing)
• Compare (1–5), Stage 3: Multiply within 100 (Supporting)

Print Formatted Materials

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