Sort by dimension
Flat shapes and solid shapes belong in different groups.
Square, triangle, circle
flat shapes
Cube, cone, sphere
solid shapes
2-D means flat. 3-D means solid.
Year 2
Compare and sort common 2-D and 3-D shapes and everyday objects
Sort shapes and objects by clear mathematical properties and explain simple groupings.
Lesson overview
Geometry - properties of shape
We can compare and sort shapes by what they have in common. A shape might be 2-D or 3-D, have curved or straight edges, roll or stack, or have a certain number of sides or faces.
Sort by movement
Some shapes roll and some stack.
Sphere, cylinder
curved surfaces help them roll
Cube, cuboid
flat faces help them stack
The shape properties explain why the object belongs in that group.
Sort everyday objects
A tin can is like a cylinder. A dice is like a cube.
Tin can
similar to a cylinder
Dice
similar to a cube
We can sort real objects using the same shape language.
Worked example
Why can a cube and a cuboid be sorted together?
3-Dflat faces
3-Dflat faces
- Look for what the two shapes have in common.
- Both are 3-D shapes.
- Both have flat faces, edges and vertices.
- So they can be sorted together as solid shapes with flat faces.
Try it
Choose the group or statement that matches the shape properties best.
Question 1
Which group has only 3-D shapes?
square, triangle
cube, cone, sphere
Question 2
Which shape is flat?
Question 3
Which shape is most likely to roll easily?
Question 4
Which everyday object is like a cylinder?
Tin can
Book
Dice
Question 5
Which statement is correct?
3-D
3-D
Common mistakes
Watch for these when working through the lesson.
- Sorting by colour or size instead of mathematical properties.
- Putting a flat shape in a 3-D group.
- Forgetting that everyday objects can be matched to shape names.
Related topics
These ideas fit closely with this lesson.
- Identify and describe the properties of 2-D shapes, including the number of sides and line symmetry in a vertical line.
- Identify and describe the properties of 3-D shapes, including the number of edges, vertices and faces.