The idea, step by step
Count sides and corners
A side is part of the boundary of a flat shape. A corner is where two straight sides meet.
Count each side and corner once. Start at a corner and travel around the shape to avoid counting it twice.
Describe a solid object
A cube has six flat square faces. A ball has a curved surface all around.
A cylinder-shaped can has two flat round ends and a curved side. Use these features rather than only colour or size.
A common trap
Every object that rolls is a ball.
Instead: Cans can roll too. Look for flat ends as well as a curved side.
See the thinking
Compare A and B
How do the triangle and square differ?
- Count around A without repeating the starting corner.
- Count around B in the same way.
A can and a ball
Both objects can roll. What feature helps tell them apart?
- Rolling alone does not identify an object.
- Check whether any surfaces are flat.
Check your understanding
Name one familiar flat shape with a curved boundary and no corners.
Show answer
For example, a circle. An oval also fits.
Both circles and ovals have a curved boundary with no corners; more than one answer is possible.
Your turn
6 questions · Work at your own pace.
Read the questions online
- How many corners does pictured shape A have?
- How many corners does pictured shape C have?
- Does a ball have flat square faces?
- Name one solid object with flat faces.
- A solid has two flat round ends and one curved side. Name a familiar example.
- Describe a square without using its colour or size.
Read the worked solutions
- How many corners does pictured shape A have?
A is a triangle.
3. - How many corners does pictured shape C have?
Trace around its four corners.
4. - Does a ball have flat square faces?
A ball is curved all around.
No. - Name one solid object with flat faces.
Check that the object has a flat surface.
Answers vary, such as a cube-shaped block or box. - A solid has two flat round ends and one curved side. Name a familiar example.
Those are the features of a cylinder.
A can or cylinder. - Describe a square without using its colour or size.
Use the defining features, not appearance alone.
Four equal straight sides and four square corners.
Curriculum reference & lesson scope
Australian Curriculum v9 / SA Curriculum 2026
Year 1 making, sorting and describing familiar shapes and objects using spatial features.
Official curriculum source ↗