☰ Year plan · Mathematics

3D shapes (2)

Week 20 · Unit 10 · 10.1 · 4 lessons
2

Same and different

Learner’s Book 1: Unit 10, p. 142
GoalSay what is the same and what is different about two 3D shapes, and name the shape of a flat face.
New words
same · not different in some waydifferent · not the sameface · a flat side of a 3D shape
Explanation

To compare two shapes, ask what is the same and what is different. A cube and a cuboid both have 6 flat faces and straight edges. On a cube all the faces are squares. On a cuboid the faces are rectangles. A sphere and a cylinder both have a curved surface, but only the cylinder has flat faces. Each flat face is a 2D shape. A cube face is a square. The end of a cylinder is a circle. A side of a pyramid is a triangle.

cube facecuboid facecylinder endpyramid side
Worked examples
cubecuboid
flat faces66
shape of facessquaresrectangles
A cube and a cuboid: both have 6 flat faces. A cube has square faces and a cuboid has rectangle faces.
cubecubespherecubecube?
A pattern can repeat. Cube, cube, sphere, cube, cube, … The next shape is a sphere.
rectangle
Look at the bottom of a cereal box. Its shape is a rectangle.
Class activity

Compare two things: pick two objects, for example a ball and a tin. Take turns to say one thing that is the same and one thing that is different. Can you find three of each?

Practice
1
What shape is the flat end of a tin can?
2
What 2D shape is a face of a cube?
3
What shape comes next?
cylinderpyramidpyramidcylinderpyramid?
4
Say one thing that is the same and one thing that is different about a cube and a square pyramid.