Primary 5 Maths: 3-D Shapes and Nets — Tutor Lesson Plan (faces, edges, vertices)

2026-10-27

Tutor lesson-prep guides · Primary maths

This chapter is not memorising numbers; it is counting something you can hold. With a box on the desk, faces, edges and vertices stop being guesses.

Objectives — the student can count faces, edges and vertices of prisms and pyramids, decide whether a net folds into a cube using opposite faces, and draw the net of a prism.

01 Prerequisites (3-minute check)

If any of these fails, fix it before the lesson starts.

Skill	Quick check	Pass mark
Names of solids	Name three solids around you	Cube, cylinder, sphere
Plane shapes	How many sides has a square?	4 sides, 4 corners
Cutting safely	Cut along a straight line	Can cut out a net

02 Lesson flow (45 minutes)

Time	Stage	Tutor does	Student does
0-6 min	Real box	Hold up a box and ask how many faces	Feel and count in turn
6-16 min	Cut it open	Cut along the edges and flatten it	Cut too, then mark opposite faces
16-26 min	Count	Fill the table for prisms and pyramids	Count once and fill in
26-36 min	Nets	Three nets: which one cannot fold?	Use “opposite faces are never adjacent”
36-42 min	Fix errors	Board the double-counted edge	Name the edge they counted twice
42-45 min	Exit check	Three questions marked at once	Finish alone

03 Teaching script (read it out)

Scene 1: Feel before counting

Do not start with 6 faces, 12 edges, 8 vertices. Feel it: top, bottom, four sides, six faces.
An edge is where two faces meet; a vertex is where three edges meet.

Student counts while touching the box, then writes the answer.

Scene 2: Opposite faces are never adjacent

On a net, two faces that share an edge become neighbours when folded, never opposites.
So to find an opposite face, look for the one with a face in between.

Student shows one pair of opposite faces and says why.

Scene 3: A prism net is two bases plus the sides

A cylinder flattens into a rectangle whose length is the circumference of the base.
A triangular prism is two triangles and three rectangles; a cuboid is two bases and four rectangles.

Note: a cylinder has 3 faces (2 flat, 1 curved), not 6.

04 Question types and worked steps

Type	Example	Steps	Answer
Cube	faces, edges, vertices	Count each once	6, 12, 8
Triangular prism	faces, edges, vertices	2 triangular bases + 3 sides	5, 9, 6
Square pyramid	faces, edges, vertices	1 base + 4 triangles	5, 8, 5
Cylinder	faces	2 flat bases + 1 curved	3 faces

Sanity check (teach this): Edges of a prism = sides of the base × 3 (triangular 3×3=9, cuboid 4×3=12). Use it to check the count.

05 Independent practice (3 questions)

Question	Answer	What to watch
Faces of a triangular prism	5	Did they count both bases?
Edges of a cube	12	Counting without repeats
Flat faces of a cylinder	2	Is the curved face counted as flat?

06 Common mistakes and what to say

Mistake	Student writes	Say this
Double counting edges	answers 14 or 16	Count one ring at the top, one at the bottom, then the uprights.
Every net folds	answers “all of them”	If opposite faces touch on the net, two faces overlap when folded.
Cylinder counted as 6 faces	answers 6	A cylinder has 3 faces: two circles and one curved surface.
Pyramid counted as a prism	12 edges for a square pyramid	A pyramid has one vertex on top and 4 side edges.

07 Homework (paper, section and question numbers)

Primary 5 first-term paper — Section C, questions 6 to 9
Primary 5 second-term paper — Section C, questions 5 to 7

08 Exit check (last 5 minutes)

Question	Answer	Decision
Square pyramid: faces, edges, vertices	5, 8, 5	All right: move to volume
Edges of a cube	12	One wrong: recount a real box next lesson
Faces of a cylinder, and how many are curved	3 faces, 1 curved	Two wrong: repeat the cutting activity

09 Tutor FAQ

What if there is no box?

Fold one from A4 paper in five minutes; a real solid beats a diagram.

Should they memorise all 11 cube nets?

No. “Opposite faces are never adjacent” is enough for primary questions.

Is counting too easy?

For Primary 5 it is the right depth; the difficulty is spatial, not arithmetic.

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A TutorZone lesson-prep guide. Written by the TutorZone team; questions and lesson flow are original and are not taken from any school or publisher material.