2D shapes and 3D objects
Know the shapes’ names, count sides and corners, and learn the faces, edges and vertices of 3D objects. Read one step, play with it, then tap “I understand this”.
2D shapes: sides and corners
A 2D shape is flat, like a picture on paper. Its name tells you how many sides it has: triangle (3), pentagon (5), hexagon (6).
The shape explorer
Tap a shape. The yellow dots count the corners.
A shape with straight sides has as many sides as corners.
Every corner is where two sides meet. Walk around the shape: after every side comes a corner, until you are back where you started.
Shapes do not have to be neat
A hexagon can be slanted and uneven. As long as it has 6 straight sides, it is a hexagon. Tests like to use slanted shapes!
Name the shape
Count the sides and choose the name.
Correct: 0
Put your finger on one corner and count all the way round. Stop when you are back at the first corner.
3D objects: faces, edges and vertices
A 3D object is one you can pick up, like a box or a ball. It has:
- Faces: the flat or curved surfaces.
- Edges: where two faces meet.
- Vertices: the corners where edges meet.
The 3D shelf
Tap an object. The dotted lines are the edges hiding at the back.
2D shapes on 3D objects
The flat faces of a 3D object are 2D shapes: a cube’s faces are squares, a cylinder’s ends are circles, and a pyramid’s sides are triangles.
Look for 3D objects in the kitchen: a tin (cylinder), a cereal box (rectangular prism), an orange (sphere) and an ice cream cone (cone).
A square is 2D and flat; a cube is 3D. Do not say “a cube has 4 sides”: it has 6 faces.
Check yourself
- 2D is flat; 3D you can pick up.
- Triangle 3, quadrilateral 4, pentagon 5, hexagon 6, octagon 8 sides.
- 3D: faces, edges (where faces meet) and vertices.
- A cube has 6 faces, 12 edges and 8 vertices.
Write these points in your maths book. Read them again the night before the test.
Quick questions
Tap an answer. If you get one wrong, read why and go back to that step. You get new questions every time.
You ticked all 4 steps! Now you are ready for the quiz.- Practice sheet for this classQuestions + memo · 2 A4 pagesPractice sheet
- Geometry7 pages · PDFPaperMemo
- Space and shape7 pages · PDFPaperMemo
Ready for more? The Grade 4 geometry quiz gives you new questions every time.
- One step a day is enough. Ten calm minutes work better than an hour the night before the test.
- Go on a shape hunt at home: who finds a cylinder, a sphere and a hexagon first (look at nuts and bolts!)?
- Ask your child to tell you the rule in their own words. If they can explain it, they understand it.
- The ticks (“I understand this”) are saved on this device only. We never ask for names or emails.
Follows CAPS for Grade 4 Maths. Always check your teacher’s notes and textbook too.