Functions Unveiled

Grade Level

9th Grade

Duration

60 minutes

Class Size

25 students

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Unit Context

Unit: Ratios and Proportions Mastery
Lesson: 14 of 16
Lesson Title: Introduction to Functions
Lesson Description:
Students will be introduced to the concept of functions as a natural extension from their prior understanding of ratios and proportions. This lesson focuses on recognizing functions from sets of data and lays a foundation for more complex function work ahead.

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Common Core State Standards (CCSS) Alignment

• CCSS.MATH.CONTENT.HSF.IF.A.1: Understand that a function from one set (domain) to another set (range) assigns to each element of the domain exactly one element of the range.
• CCSS.MATH.CONTENT.HSF.IF.A.2: Use function notation, evaluate functions for inputs in their domains, and interpret statements that use function notation in terms of a context.
• CCSS.MATH.PRACTICE.MP1: Make sense of problems and persevere in solving them.
• CCSS.MATH.PRACTICE.MP4: Model with mathematics.
• CCSS.MATH.PRACTICE.MP6: Attend to precision.

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Learning Objective & "I Can" Statement

Learning Objective:
Students will understand the relationship between inputs and outputs in a function and identify whether a given relation represents a function.

"I Can" Statement:
I can understand the basics of functions and identify functions from given sets of data.

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Success Criteria

• I can explain what a function is using my own words.
• I can determine if a relation is a function by looking at sets of ordered pairs or tables.
• I can use function notation to express a function.
• I can explain why a set of data is or isn’t a function.

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Materials Needed

• Projector or SMARTboard
• Whiteboard and markers
• Dyslexia-friendly printouts (use a font like OpenDyslexic or Comic Sans, 14-16 pt size, left-aligned text, with shaded backgrounds for easier reading)
• Graph paper
• Individual mini whiteboards and markers for each student
• Index cards with sets of ordered pairs (some representing functions, some not)
• Function input-output machine visual aids (box diagrams)
• Timer/clock for activity pacing

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Lesson Breakdown

1. Warm-Up: Quick Ratio Review & Transition (8 minutes)

• Activity:
  Project 3 simple ratio problems, ask students in pairs to write the ratio and find equivalent ratios.
• Teacher Talk:
  Explain how those ratio inputs and outputs lead us to thinking about function relationships, introducing the term "function."

Dyslexia tip: Provide simple text slides with high contrast colors (light background, dark text). Use bullet points.

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2. Direct Instruction: What Is a Function? (12 minutes)

• Explain:
  Define a function as “a rule that assigns each input exactly one output.”
  Use real-life examples (e.g., vending machines: for each button pressed (input), you get one drink (output)).

• Visual:
  Use a function machine diagram (input box → function rule → output box).
  Demonstrate simple function notation: ( f(x) = 2x + 1 ).

• Check for Understanding:
  Ask students: “Can one input lead to more than one output in a function?”
  Clarify with examples and non-examples.

Dyslexia tip: Use visuals with minimal text, icons, and colors to segment information.

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3. Guided Practice: Identifying Functions (15 minutes)

• Activity:
  Distribute index cards with ordered pairs, tables, and mappings. Students work in groups of 3-4.

• Task:
  Sort the sets into "Function" and "Not a Function" categories.
  Write brief reasons for their choices on mini whiteboards.

• Teacher Circulates:
  Monitor groups, ask probing questions, and provide feedback.

Dyslexia tip: Provide printed instructions that are clear and concise, with bullet points.

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4. Whole-Class Discussion (10 minutes)

• Groups share one example each and explain why it is or isn’t a function.
• Use student contributions to reinforce concepts, note function characteristics on the board.

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5. Individual Practice: Function Notation & Evaluation (10 minutes)

• Worksheet Activity:
  Students complete problems evaluating simple functions, e.g.,

  ( f(x) = 3x - 4 ), find ( f(2) ), ( f(-1) ).

• Extension:
  Students write their own function rule for a simple real-world situation.

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6. Closure & Success Criteria Review (5 minutes)

• Review the "I can..." statements aloud.
• Quick quiz-style exit ticket: Provide 3 sets of ordered pairs; students write "Function" or "Not a Function" on index cards.

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Assessment

• Formative: Group sorting activity and class discussion participation.
• Summative: Exit ticket answers.
• Optional: Homework to identify functions from a data set and write function notation.

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Modifications & Dyslexia-Friendly Practices

• Use dyslexia-friendly font and text formatting in printouts.
• Provide ample white space and avoid large blocks of text.
• Include visuals and color coding to support understanding.
• Speak clearly, repeat key ideas, and allow students to ask clarifying questions.
• Offer oral reading support if needed.

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Reflection for Teachers

• Did students grasp the concept that each input has exactly one output in a function?
• Were students able to distinguish functions from non-functions confidently?
• Which activities engaged students the most?
• Are there students needing additional support before moving deeper into function notation in later lessons?

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End of plan.