## Whats A Function.pdf - Section 2: What is a function?

# What's My Rule?

Lesson 4 of 19

## Objective: SWBAT to assign a rule/equation to given a table of data.

## Big Idea: Looking for patterns is just the start of this wonderful activity that helps students begin to see relationships in given data sets and express those relationships as equations or rules.

*42 minutes*

### Heather Sparks

#### Warm Up

*5 min*

For Warm Up today, I have selected several problems that require students to apply previously learned rules of exponents. Negative exponents continue to confuse students, so I intentionally bring them back at least once a week. I also included two problems that involve computations with scientific notation. By providing spiral review of these problems, students gain confidence in their probelm-solving abilities.

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#### What is a function?

*7 min*

Understanding a function is the main idea of this entire unit, so I want to give focus to this key academic vocabulary. I provide the definition of a function for students to include in their journal. I then go on to show an example and a non-example of a function (represented by two different data sets) so that students have a visual representation of the definition. Although the students can easily identify the non-function having a double input value, it is not until I plot the points on the graph that they see it graphically. I briefly mention the vertical line test and show how the non-function does not pass the test. I will address the vertical line test again later in the unit, so I don't spend time practicing it in this lesson.

#### Resources

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#### Let's Play: What's My Rule?

*24 min*

Next, I introduce today's activity, a game called "What's My Rule?". I reveal a table of values in which I have shaded the y-values from student view. I explain that for each input, something is going to happen to change the number. Their job is to figure out what is happening based on the y-value (output) numbers. I explain the rules of the game: First, no one can call out the rule. They can only say the word "rule" at which point I will call on them to tell me the next output. After they call the output, I reveal it. If they are correct, I tell them they have the rule. If they are incorrect, I encourage them to keep thinking. I continue with other students until we have revealed the entire chart. I then ask for a volunteer to give me the rule.

The rules for the first four data tables are very simple and student confidence builds quickly. Then, I reveal table #5, which has a two-step rule applied. This stumps students for a bit, but eventually someone calls, "rule", so we test their idea.

If students get stumped, I explain that sometimes, a rule has two steps, like a two-step equation. This generally gets students headed in the right direction.

#### Resources

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For closure, I want students to create their own rule and then fill in a corresponding t-table. I distribute note cards and tell them to create a rule in slope-intercept form on the front and a table of values for that rule on the back. I model an example on the smartboard so they know what to do. As they leave class, I collect these cards. My plan is to use them in the next day's lesson.

#### Resources

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- UNIT 1: Welcome Back!
- UNIT 2: Rules of Exponents
- UNIT 3: How Big? How Small?
- UNIT 4: So What's Rational About That?
- UNIT 5: The Fabulous World of Functions
- UNIT 6: Shapes On A Plane
- UNIT 7: What's at the Root?
- UNIT 8: Playing Around with Pythagoras
- UNIT 9: Quantum of Solids
- UNIT 10: It's All About the Rates
- UNIT 11: Oni's Equation Adventure

- LESSON 1: Fabulous World of Function- Unit Introduction
- LESSON 2: Turtle & Snail Part I : An Introduction to "Rule of Five'
- LESSON 3: Turtle & Snail Part II
- LESSON 4: What's My Rule?
- LESSON 5: What's My Rule? Technology Mode
- LESSON 6: Writing Function Rules
- LESSON 7: Rule of 5 Poster Project
- LESSON 8: Charity Walk-A-Thon
- LESSON 9: Which T-Shirt Company?
- LESSON 10: Right Hand/Left Hand
- LESSON 11: Penny Bridges
- LESSON 12: Penny Bridge Debrief
- LESSON 13: What's the Correlation?
- LESSON 14: Slinky Stretch Lab
- LESSON 15: Cup Stacking
- LESSON 16: Gas Guzzlers
- LESSON 17: Rule of 5 Card Match
- LESSON 18: Here Comes Halley!
- LESSON 19: Buying a Ford Mustang