Unit #4: Perimeter and Area Explorers

Lesson 4: Introduction to Area

Duration: 60 minutes
Year Level: Year 3–4
Curriculum Area: Mathematics and Statistics
Strand: Geometry and Measurement
Achievement Objective (Level 2 of The New Zealand Curriculum):

"Measure the area of objects using non-standard and standard units."

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Learning Intentions

By the end of this lesson, students will:

• Understand area as the space inside a 2D shape
• Be able to estimate and count square units to measure area
• Begin connecting the idea of area with real-world contexts

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Success Criteria

Students will be successful when they can:

• Correctly use square units to measure area
• Represent area of simple shapes using grid paper
• Explain, in their own words, what area means

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Materials Needed

• A3 square centimetre grid paper (1 per student + extras)
• Scissors
• Pre-cut 2D shapes (rectangles, triangles, irregular shapes)
• Whiteboard and markers
• Floor tiles or masking tape square on floor
• Paper cut-out of a pretend "Area Explorer Passport"
• Coloured pencils/felts
• Large visual cue cards with terms: Area, Square Unit, Shape, Inside Space

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Learning Sequence

1. Tuning In: "Space Detective" (10 minutes)

Purpose: Activate prior knowledge and introduce new vocabulary.

• Begin by asking the class: "Have you ever thought about how much space is inside your lunchbox lid?"
• Use a large cut-out of a rectangle and ask students: "How could we find out how much space is inside this shape?"
• Display a picture of a house and ask them to imagine laying tiles on the kitchen floor — each tile fills some space.
• Introduce the word area using a picture-thinking prompt: "Area is all the space inside a shape. It tells us how much space something covers!"

💡 Teacher tip: Use the classroom floor tiles or a taped square on the floor to demonstrate standing inside the shape.

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2. Whole-Class Modelling: Area with Grid Paper (10 minutes)

Purpose: Introduce the concept of square units.

• Use a large rectangle on grid paper under the visualiser or on the whiteboard.

• Model counting the squares:

  • "How many squares does it take to completely fill this shape?"
  • Model counting systematically (row by row).
  • Write Area = 10 square units (you may also write cm² depending on familiarity).

• Repeat with a different shape with partial squares. Discuss:

  • "If it’s only half a square, what should we do?"
  • Encourage estimation and discussion.

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3. Guided Practice: My Area Explorer Passport (20 minutes)

Purpose: Hands-on exploration with teacher guidance

Students receive a booklet or card titled "Area Explorer Passport."
They complete 3 activities on their journey to become certified Area Explorers:

• Challenge 1: Rectangle Ride

  • Students draw and cut out a rectangle on grid paper.
  • Count and record area (in square units) inside their Passport.

• Challenge 2: Shape Smarts

  • Teacher gives each group 3 pre-cut different shaped figures (including irregular).
  • Students estimate, then count the area using the grid and record on their Passport.

• Challenge 3: Make-a-Shape

  • Students create their own shape that has an area of exactly 12 square units.
  • They draw and colour it, then swap with a partner to check!

🧠 Differentiation Tip: Support-struggling students by providing shapes with grid lines already drawn. Extend confident students with unusual shapes or introducing halved squares.

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4. Sharing and Discussion (10 minutes)

Purpose: Consolidate learning through peer interaction and teacher feedback.

• Students pair up to share their Passport (especially Challenge 3).
• Ask reflective questions:
  • "What did you learn about how area works?"
  • "Why is counting squares carefully important?"
  • "Did different shapes ever have the same area?"

Bring everyone together and highlight a few creative student shapes on the board.

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5. Wrap-Up and Reflection (5 minutes)

Whole Class Discussion:

• Revisit the Learning Intention.
• Add to a class chart: “What Area Means to Us”
  • Add student definitions or drawings.

🎒 Exit Ticket: Before leaving, each student must answer one of these out loud:

• "What is area?"
• "How do we measure it?"
• "Can two different shapes have the same area?"

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Assessment Opportunities

• Informal observation during practical tasks
• Review completed Area Explorer Passports
• Notes from partner-share discussions
• Responses during Exit Ticket

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Next Steps

In Lesson 5, students will begin applying their understanding of area to real-world classroom objects, estimating and measuring using standard units (cm²). They will create a classroom area map!

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Integration Opportunities

• Art: Use grid paper to create mosaic patterns with specific area targets.
• P.E.: Measure the area of play spaces using body-sized grid tiles (e.g., hula hoops or taped squares).
• Te Reo Māori: Introduce terms such as rohe (area/region), rōrahi (volume), building bicultural vocabulary connections.

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Teacher Reflection Questions

• Which students showed a strong conceptual understanding of area?
• Did students demonstrate estimation strategies or rely purely on counting?
• How can learning be extended through localising context, e.g., measuring spaces in our school wharenui or gardens?

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Key Vocabulary

• Area
• Square unit
• Estimate
• Measure
• Space
• Inside

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"We are not just measuring shapes – we are measuring space, creativity, and thinking!"
Let your ākonga be the explorers in this mathematical journey. 🌏📏