Grade 3 · Math · Unit 12 of 14
3D Objects
Faces, edges and vertices
What your child practises
Naming 3D objects, counting their faces, edges and vertices, and thinking about how they are built from flat faces or from straws and clay.
Nunavut Curriculum approved guide: Alberta Mathematics K–9 (2007), Shape and Space · describing 3-D objects by their faces and edges
How we explain it
Children can open this short lesson before they practise.
- A face is a flat side.
- An edge is where two faces meet.
- A vertex is a corner.
Example: How many faces does a cube have? A cube is shaped like a die. A die has 6 flat faces. Answer: 6
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
How many edges does a cube have?
answer box
12
Hint: An edge is where two faces meet. There are 4 edges around the top, 4 around the bottom and 4 going up the sides: 12.
Question 2
A brick is shaped most like a…
🧱- rectangular prism
- cone
- pyramid
- cylinder
rectangular prism
Hint: Look at its faces. Are they flat or curved? A rectangular prism is shaped like a box. Its faces are rectangles.
Question 3
Which 3D object has exactly one flat face?
- sphere
- cone
- cube
- cylinder
cone
Hint: A cone has just 1 flat circle on the bottom.
Question 4
What is this 3D object called?
- sphere
- cone
- cube
- rectangular prism
cone
Hint: A cone has 1 flat circle face and a curved side that comes to a point.
Question 5
Zoe builds a 3D object out of paper using 1 circle and a curved piece rolled into a point. What did Zoe build?
- cube
- pyramid
- rectangular prism
- cone
cone
Hint: Think about which object has those faces. A cone has 1 flat circle face and a curved side that comes to a point.
Question 6
What shape are the slanted faces of a pyramid?
- circle
- hexagon
- square
- triangle
triangle
Hint: The slanted faces of a pyramid are triangles that meet at a point on top.