Shapes Around Us — Class 4 Mathematics (CBSE)

From the current NCERT Maths Mela Grade 4 book, Chapter 1. Shapes are everywhere — let us look at flat shapes, solid shapes, and how they connect.

1. Why this chapter matters

The world is full of shapes — flat ones like a window, and solid ones like a box or a ball. Knowing the names of shapes and their parts (faces, edges, corners) helps us describe objects, build models, and see patterns around us.

2. Core ideas

Idea 1 — Flat (2D) and solid (3D) shapes

2D shapes are flat: square, rectangle, circle, triangle. 3D shapes are solid: cube, cuboid, sphere, cylinder, cone, prism, pyramid.

Method 2 — Solids have faces, edges, and corners

A face is a flat or curved 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.

Skill 3 — A net folds into a solid

A net is a flat shape that folds to make a 3D shape. A cube's net is 6 squares joined together.

3. Worked examples

Example 1: How many faces, edges, and corners does a cube have?

A cube has 6 faces, 12 edges, and 8 corners.

Example 2: Name the 2D faces of a cuboid (matchbox).

Its faces are rectangles (6 rectangular faces).

Example 3: Which solid has a curved surface and rolls?

A sphere (also a cylinder and a cone have curved surfaces).

4. Activity corner

Cut out a net of 6 squares and fold it into a cube. Then collect three objects and note their shapes. Write:

• The net you folded and the solid it made
• Three objects and their solid shapes
• The maths idea (faces, edges, corners of solids)

5. Common mistakes

• Mistake: Confusing a 2D shape with a 3D shape (square vs cube). Fix: A square is flat (2D); a cube is solid (3D).
• Mistake: Mixing up edges and corners. Fix: An edge is a line where two faces meet; a corner is a point where edges meet.
• Mistake: Thinking any 6 squares make a cube net. Fix: Only certain arrangements of 6 squares fold into a cube.

6. How to write better answers

1. Say whether the shape is 2D (flat) or 3D (solid).
2. Name the shape.
3. Give its faces, edges, and corners if it is a solid.
4. Add a real object as an example.

7. Practice set

1. Name two 2D shapes and two 3D shapes.
2. How many faces, edges, and corners does a cube have?
3. What 2D shape are the faces of a cuboid?
4. Name a solid that has a curved surface.
5. How many squares are in the net of a cube?
6. Is a football a 2D or a 3D shape? Name it.

8. Answer key

1. 2D: square, circle; 3D: cube, sphere (answers may vary).
2. 6 faces, 12 edges, 8 corners.
3. Rectangles.
4. A sphere (or cylinder, or cone).
5. 6 squares.
6. 3D; it is a sphere.

9. Quick revision

• 2D shapes are flat; 3D shapes are solid.
• Solids have faces, edges, and corners.
• A cube: 6 faces, 12 edges, 8 corners.
• A net folds into a solid (a cube net = 6 squares).
• Sphere, cylinder, and cone have curved surfaces.