Two-Dimensional Shapes - First Grade
1. Name the Two-Dimensional Shape
Concept: A 2D shape is a flat shape that has only length and width, no thickness. We can draw them on paper!
Basic 2D Shapes:
Circle
Round shape
Square
4 equal sides
Rectangle
4 sides, 2 long & 2 short
Triangle
3 sides
Diamond
4 equal sides (tilted)
Oval
Stretched circle
💡 Tip: Look around your house - can you find these shapes? A plate is a circle, a book is a rectangle!
2. Select Two-Dimensional Shapes
Concept: Learn to identify and choose specific shapes from a group of different shapes.
How to Identify Shapes:
1. Count the number of sides
2. Look at the corners (vertices)
3. Check if sides are equal or different lengths
4. See if it has curves or only straight lines
Shape Checklist:
✓ Circle: No sides, no corners, round
✓ Triangle: 3 sides, 3 corners
✓ Square: 4 equal sides, 4 corners
✓ Rectangle: 4 sides (2 long, 2 short), 4 corners
💡 Tip: Look carefully at each shape's features before choosing!
3. Count Sides and Vertices
Concept: Learn what sides and vertices are, and how to count them in different shapes.
📏 Sides
A side is a straight line that forms part of a shape.
Also called: Edges
🔺 Vertices
A vertex is a corner where two sides meet.
More than one = Vertices
Counting Guide:
Triangle: 3 sides, 3 vertices
Square: 4 sides, 4 vertices
Rectangle: 4 sides, 4 vertices
Pentagon: 5 sides, 5 vertices
Hexagon: 6 sides, 6 vertices
Circle: 0 sides, 0 vertices (curved shape!)
💡 Tip: Use your finger to trace each side and touch each corner to help you count!
4. Compare Sides and Vertices
Concept: Compare different shapes to see which has more or fewer sides and vertices.
Comparison Examples:
Example 1: Triangle vs Square
• Triangle: 3 sides, 3 vertices
• Square: 4 sides, 4 vertices
✓ Square has MORE sides and vertices than triangle!
Example 2: Pentagon vs Triangle
• Pentagon: 5 sides, 5 vertices
• Triangle: 3 sides, 3 vertices
✓ Pentagon has 2 MORE sides and vertices than triangle!
Example 3: Square vs Rectangle
• Square: 4 sides, 4 vertices
• Rectangle: 4 sides, 4 vertices
✓ They have the SAME number of sides and vertices!
💡 Tip: Count first, then compare! Use words like "more," "fewer," or "same."
5. Open and Closed Shapes
Concept: Learn the difference between shapes that are closed (all connected) and open (have gaps).
✅ Closed Shape
All sides are connected. No openings or gaps. You can't escape from inside!
Closed Square
❌ Open Shape
Has a gap or opening. At least one side is not connected. You could escape!
Open Shape
Examples:
✓ Closed: Circle, Square, Triangle, Rectangle
✗ Open: Letter C, Letter U, Incomplete circle
💡 Tip: All true 2D shapes (polygons) are closed shapes!
6. Flip, Turn and Slide
Concept: Shapes can move in three different ways - flip, turn, and slide. These are called transformations!
🔄 Slide (Translation)
The shape moves in a straight line to a new position. It doesn't turn or flip. Same direction!
◼️ → → → ◼️
The square slides to the right
🪞 Flip (Reflection)
The shape flips over like looking in a mirror. It creates a mirror image!
◀ | ▶
The triangle flips across the line
🔃 Turn (Rotation)
The shape rotates around a point. It can turn a little or a lot - clockwise or counterclockwise!
▲ → ▶ → ▼ → ◀
The triangle turns around
Remember:
• Slide = Move straight
• Flip = Mirror image
• Turn = Rotate around
💡 Tip: Cut out paper shapes and practice sliding, flipping, and turning them!
7. Symmetry
Concept: A shape has symmetry when one half is a mirror image of the other half. We can fold it perfectly in half!
Line of Symmetry:
A line of symmetry divides a shape into two identical halves. Each half is a mirror image!
Examples of Symmetrical Shapes:
✓ Circle: Infinite lines of symmetry (any line through center)
✓ Square: 4 lines of symmetry
✓ Rectangle: 2 lines of symmetry
✓ Equilateral Triangle: 3 lines of symmetry
✓ Heart: 1 line of symmetry (vertical)
How to Test for Symmetry:
1. Draw or imagine a line through the middle
2. Check if both sides match exactly
3. If you can fold the shape and both halves line up perfectly, it has symmetry!
💡 Tip: Look for symmetry in nature - butterflies, leaves, and faces have symmetry!
Shape Quick Reference Chart
| Shape | Sides | Vertices | Special Features |
|---|---|---|---|
| Circle | 0 | 0 | Curved, round |
| Triangle | 3 | 3 | 3 straight sides |
| Square | 4 | 4 | All sides equal |
| Rectangle | 4 | 4 | 2 long, 2 short sides |
| Pentagon | 5 | 5 | 5-sided shape |
| Hexagon | 6 | 6 | 6-sided shape |
Important Shape Vocabulary
- 2D Shape: A flat shape with length and width (no thickness)
- Side: A straight line that forms part of a shape
- Vertex: A corner where two sides meet (plural: vertices)
- Closed Shape: All sides connected with no gaps
- Open Shape: Has at least one gap or opening
- Symmetry: When one half mirrors the other half exactly
- Slide: Moving a shape in a straight line
- Flip: Creating a mirror image of a shape
- Turn: Rotating a shape around a point
🎯 Tips for Shape Success 🎯
- ✓ Count sides and vertices by tracing with your finger
- ✓ Look for shapes in everyday objects around you
- ✓ Use paper cutouts to practice flips, turns, and slides
- ✓ Test for symmetry by folding paper shapes in half
- ✓ Draw your own shapes and label sides and vertices
- ✓ Play shape scavenger hunts at home or school!
⭐ You're a Shape Expert! ⭐
Amazing work learning about 2D shapes! You now know how to name them, count their parts, and move them around. Shapes are everywhere - keep discovering!