# Teacher Sample

### 8th Grade Standard - 8.NS.A.2

#### The Number System

#### 8.NS.A.2

Use rational approximations of irrational numbers to compare the size of irrational numbers, locate them approximately on a number line diagram, and estimate the value of expressions (e.g., π 2 ). For example, by truncating the decimal expansion of √2, show that √2 is between 1 and 2, then between 1.4 and 1.5, and explain how to continue on to get better approximations.

# LESSON: TREASURE HUNT

### How far away is the final map point?

The best way to visualize and use irrational numbers is to approximate them with a decimal. In Treasure Hunt, Caterina Fenn hires Tiberius Picklebottom to help her find her grandfather’s hidden treasure. Based on a map and a few calculations, Tiberius determines the distance to the treasure is √2 miles. They must approximate this distance in order to use the theodolite (the measuring device), and want to be as accurate as possible to minimize their digging efforts.

# Day 1

#### Act 1

1. Play Treasure Hunt Act 1 Video, whole class.

2. Restate the question: **How far away is the final map point?**

3. Ask students: "What are your ideas to help the Professor?"

4. Facilitate classroom discussion.

#### Act 2

1. Print the data artifact page, cut into halves, and distribute to students.

2. Allow students work time. Then ask students "Does your answer make sense?"

3. Consider using a sharing protocol to lead to mathematical insights and/or highlight misconceptions.

4. Allow students to revise their work.

#### Act 3

1. Play Treasure Hunt Act 3 Video, whole-class.

2. Allow students final revisions to their work, if necessary.

3. Give Student Reflection Assignment.

Answer: The final map point and treasure is approximately 1.41 miles away!

# Day 2

1. Print and distribute the Practice Printable to your students.

2. Print the Teacher Answer Key.

3. Give a short 5-7 minute teacher lecture on the concept of the standard.

4. Have students complete the Practice Printable and finish the Day 1 Student Reflection Assignment.

# Day 3

1. Have your students go to midschoolmath.com/clicker.

2. Click on Launch Clicker Quiz and note Clicker Quiz #.

3. Have students enter quiz code on their screens.

4. Launch clicker quiz.

5. Review clicker quiz results and prompt students to make connections to the 3-Act Math Task.

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