🔷 Topics & explainers · 5 min read
Basic shapes for Class 4: sides, corners, faces and edges
A Class 4 explainer of 2D and 3D shapes — counting sides, corners, faces and edges, with the square-vs-rhombus trap from SOF IMO geometry.
Shapes come in two families. Flat (2D) shapes like triangles, squares and hexagons have sides and corners. Solid (3D) shapes like cubes, spheres and cones have faces, edges and corners you could hold in your hand. Class 4 geometry is mostly about naming these shapes and counting their parts correctly — and olympiad questions test the properties, not just the names.
The idea in one minute
- 2D shapes: a triangle has 3 sides and 3 corners; a quadrilateral has 4; a pentagon 5; a hexagon 6; an octagon 8.
- A circle has no straight sides and no corners at all.
- 3D shapes: a face is a flat surface, an edge is where two faces meet, a corner (vertex) is where edges meet. A cube has 6 faces, 12 edges and 8 corners.
- Special quadrilaterals: a square has 4 equal sides and 4 square corners; a rectangle has square corners but only opposite sides equal; a rhombus has 4 equal sides but slanted corners.
✏️ Warm-up: count the sides
How many sides does a hexagon have?
- A5
- B6
- C7
- D8
Show the answerAnswer: 6
Answer: 6. Hex- means six: a hexagon has 6 sides and 6 corners. The neighbours in the options are the pentagon (5 sides) and the octagon (8 sides) — worth learning as a family so the names stop being confusable.
✏️ Level up: corners of a cube
How many corners (vertices) does a cube have?
- A6
- B8
- C12
- D4
Show the answerAnswer: 8
Answer: 8. Picture a dice: four corners on the top face and four on the bottom face make 8 corners in all. The trap options are the cube’s other counts — it has 6 faces and 12 edges — so the question is really testing whether a child knows which word means what.
✏️ Olympiad twist: name the shape from its properties
A flat shape has 4 sides, all equal in length, but its corners are not square corners. What is it?
- ASquare
- BRectangle
- CRhombus
- DTrapezium
Show the answerAnswer: Rhombus
Answer: Rhombus. Four equal sides narrows it to a square or a rhombus. A square’s corners are all square (right angles), and the question rules that out — so the shape is a rhombus, a pushed-over square. A rectangle has square corners but unequal neighbouring sides, and a trapezium does not need any equal sides.
Shapes and their properties open LittleMathematicians’s Class 4 Geometry topic — early levels are picture-based naming, and later ones move to property riddles like the last example as mastery builds. It is free during early access, and geometry is often the topic children pick first.
Practice this the fun way
Adaptive levels, exam-pattern mocks and progress you can see — free during early access.
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