Mathematics · Grade 1

Active learning ideas

Identifying 2D Shapes

Active learning helps students grasp the defining attributes of 2D shapes because movement and hands-on work make abstract concepts concrete. When children manipulate shapes, they experience firsthand how sides, corners, and closed boundaries define a shape rather than its color or position.

• Ontario Curriculum Expectations
• 1.G.A.1

• 15–30 min
• Pairs → Whole Class
• 3 activities

Activity 01

• Gallery Walk
• 30 min · Pairs

Gallery Walk: Shape Scavenger Hunt

Students walk around the classroom or schoolyard in pairs to find 2D and 3D shapes. They take photos or draw what they find, then label them based on their attributes (e.g., 'This door is a rectangle because it has 4 sides and 4 square corners').

Differentiate between a square and a rectangle based on their attributes.

Facilitation Tip

During the Gallery Walk, position yourself where you can observe which students are naming shapes by appearance rather than by sides and corners.

What to look for

Present students with a collection of shape cutouts (squares, rectangles, triangles, circles, hexagons) mixed with some non-examples (e.g., an open shape, a shape with curved sides). Ask students to sort the shapes into two groups: 'Polygons' and 'Not Polygons', then sort the polygons by name.

• Understand
• Apply
• Analyze
• Create
• Relationship Skills
• Social Awareness

Activity 02

• Think-Pair-Share
• 15 min · Pairs

Think-Pair-Share: Mystery Bag

One student feels a 3D solid inside a bag and describes its attributes (e.g., 'It has no flat faces, it is round') to their partner. The partner must guess the shape before it is revealed.

Explain what makes a triangle a triangle regardless of how it is turned or its size.

Facilitation Tip

In the Mystery Bag activity, circulate to listen for students who describe shapes using non-defining attributes like 'big' or 'blue' instead of 'three sides' or 'four equal sides'.

What to look for

Hold up a square and a rectangle. Ask: 'How are these shapes the same? How are they different? What makes a square a special kind of rectangle?' Listen for student responses that focus on the number of equal sides.

• Understand
• Apply
• Analyze
• Self-Awareness
• Relationship Skills

Activity 03

• Formal Debate
• 20 min · Small Groups

Formal Debate: Is it a Triangle?

The teacher shows a variety of three-sided figures, some with open gaps or curved lines. Students must argue why a figure is or is not a triangle based on the rules (closed shape, three straight sides).

Construct a drawing that includes at least three different 2D shapes.

Facilitation Tip

For the Structured Debate, provide sentence stems like 'I agree because...' or 'I disagree because...' to scaffold productive discussion.

What to look for

Give each student a piece of paper with a drawing of a triangle that is rotated or a different size. Ask them to write one sentence explaining why it is still a triangle and to draw a square and a hexagon on the back, labeling each.

• Analyze
• Evaluate
• Create
• Self-Management
• Decision-Making

A few notes on teaching this unit

Teachers should model using geometric language consistently and avoid reinforcing misconceptions by referring to rotated squares as 'diamonds'. Provide multiple examples and non-examples of each shape to build flexible thinking. Research shows that students benefit from comparing shapes side by side to notice subtle differences in defining attributes.

Students will confidently identify shapes by their defining attributes and explain why non-defining attributes, like size or orientation, do not change a shape's identity. They will use precise vocabulary and justify their reasoning during discussions and activities.

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Watch Out for These Misconceptions

• During the Gallery Walk, watch for students naming a rotated square as a 'diamond' instead of a square.

  During the Gallery Walk, hand students the rotated square and ask them to count the sides and corners. Have them compare it to a square that is not rotated, asking, 'What stays the same?'.

• During the Mystery Bag activity, watch for students calling a sphere a 'circle' when feeling the object.

  During the Mystery Bag activity, ask students to try to stack or roll the object. Guide them to notice that a circle can be a flat face of a sphere but cannot roll like a sphere.

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Methods used in this brief

• Gallery Walk
• Think-Pair-Share
• Formal Debate