# Lesson 26

Book Drive (optional)

### Lesson Purpose

The purpose of this lesson is for students to apply their understanding of working with decimal numbers in an applied context.

### Lesson Narrative

This lesson is optional because it does not address any new mathematical content standards. This lesson does provide students with an opportunity to apply precursor skills of mathematical modeling. The purpose of this lesson is for students to build on their previous understanding and experiences with decimal numbers. In this lesson, students plan a school book fair. They consider different categories of books to order and the sale price of the books. They estimate the number of people likely to attend the fair and approximate the amount of money the school can make from sales.

School book fairs are common events in many schools and are often used as fundraisers. Depending on how familiar students are with this context, more or less of an introduction is necessary.

When students think about the variables in a problem, make choices and assumptions, and make estimates, they model with mathematics (MP4).

• Engagement
• MLR6

### Learning Goals

Teacher Facing

• Add and subtract decimals to the hundredths using strategies based on place value.
• Multiply decimals with products resulting in the hundredths using place value reasoning and properties of operations.

### Student Facing

• Let’s plan a book sale fundraiser.

### Lesson Timeline

 Warm-up 10 min Activity 1 20 min Activity 2 20 min Lesson Synthesis 10 min

### Teacher Reflection Questions

Reflect on how comfortable your students are asking questions of you and of each other. What can you do to encourage students to ask questions?

### Suggested Centers

• Compare (1–5), Stage 6: Add and Subtract Fractions (Supporting)
• Would You Rather? (2–5), Stage 2: Compare to Smaller Units (Supporting)