**Week 8**

**Subject: Mathematics**

**Class: Primary 3**

**Term: 3 ^{rd} Term**

**TOPIC: Shapes**

**SUBTOPIC:�� 3-dimensional shapes**

**BEHAVIOURAL OBJECTIVES: At the end of the lesson, pupils should be able to:**

**Distinguish between open and close shapes****State the properties of close shapes****Appreciate the presence and use 3 dimensional shapes in Homes.****Identify right angle,acute and obtuse andle in a plane shape.****Distinguish between horizontal and vertical.**

**CONTENT**

**Cube**

A cube has 8 vertices

A cube has 12 equal edges

A cube has 6 equal faces

**Cuboid**

A cuboid has 8 vertices

A cuboid has 12 unequal edges

A cuboid has 6 unequal faces

**Cylinder**

A cylinder has one curved face

It has two flat faces

It has no vertex

**Sphere**

A sphere has one curved face only.

Curved face

It has no edge and no vertex.

**Cone**

A cone has 1 vertex

A cone has 1 curved face

A cone has 1 flat face (i.e. a closed cone)

A cone has 1 edge

**Exercise**

**Object� � � � � � � � � � � � � �Number of vertices��� Number of edges���� �Number of faces**

- Maggi cube
- Die
- Concrete block
- Tin of milk
- Football
- Sugar cube
- Ice-cream cone
- Box
- Class-room

**Exercise 1**

Study the pictures above along with other solid objects around the class

and classify them into open and closed objects.

**Observations**

- Open object do not have a cover at the top. The inside of an open object can be seen,

because it has no cover or top face.

- The inside of a close object cannot be seen because of the cover or top face.

**Study this table carefully**

**� � � � � � � � � � � � � � � � � � � � � �Open object���������������������������� Closed object**

Cube No of vertices� � � � � � � � � � � �8� � � � � � � � � � � � � � � � � � � � � � 8

No of edges� � � � � � � � � � � � � � � � �12� � � � � � � � � � � � � � � � � � � � � 12

No of faces� � � � � � � � � � � � � � � � � �5� � � � � � � � � � � � � � � � � � � � � � 6

Cuboid No of vertices� � � � � � � � � � 8� � � � � � � � � � � � � � � � � � � � � � �8

No of edges� � � � � � � � � � � � � � � � �12� � � � � � � � � � � � � � � � � � � � � �12

No of faces� � � � � � � � � � � � � � � � � �5� � � � � � � � � � � � � � � � � � � � � � �6

Cylinder No of curved faces� � � � � � 1� � � � � � � � � � � � � � � � � � � � � � 1

No of flat faces� � � � � � � � � � � � � � � 1� � � � � � � � � � � � � � � � � � � � � � 2

No of vertices� � � � � � � � � � � � � � � � 0� � � � � � � � � � � � � � � � � � � � � � 0

**Note:**

- Tubes, pipes, straws are special cylinders with no flat face. They are known as hollow

cylinders. The two ends are open.

- A sphere is always a closed objects.

**Exercise 2**

**Copy and complete this table, stating whether the following solids are open or closed objects.**

**Name of shape���� Open����������� Closed**

Bucket

Cup

Refrigerator

Ice-cream cone

Ludo die

Cube of sugar

Tin of milk

Tin of Milo

Tin of tomato

�

**Copy and complete the table drawn below.**

**Number of faces���� Number of edges������ Number of vertices**

closed cube

closed cuboid

open cube

open cuboid

closed cylinder

open cylinder

sphere

cone

�

**Copy and complete the following.**

- A three-dimensional shape having equal faces _____________.
- A cuboid has _____________ unequal faces.
- The face of a cuboid is a _____________.
- A cylinder has _____________ flat circular faces.
- A cone has _____________ edge.
- An open shoe box has _____________ faces

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