Primary 5 Maths: Volume of Cuboids and Cubes — Tutor Lesson Plan (litres, backwards)

2026-10-27

Tutor lesson-prep guides · Primary maths

Most volume errors are a misplaced decimal point and cm² written where cm³ belongs. This lesson builds the formula from one layer of cubes.

Objectives — the student can explain V = length × breadth × height as layers of cubes, convert 1 L = 1000 cm³, and find a missing height from a volume.

01 Prerequisites (3-minute check)

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

Skill	Quick check	Pass mark
Rectangle area	Length 6, width 4	24 cm²
Multiplication	12 × 5 × 4	240
Decimal multiplication	2.5 × 4	10

02 Lesson flow (45 minutes)

Time	Stage	Tutor does	Student does
0-6 min	One layer	Build one layer of cubes and count it	Count 12 cubes
6-14 min	Stack	Stack 5 layers and ask for the total	60 cubes, written 12 × 5
14-24 min	Formula and units	Write V = l × b × h and cm³	Write units on every answer
24-34 min	Litres	1 L = 1000 cm³, two examples	2.5 L = 2500 cm³
34-42 min	Backwards	Show 240 ÷ (12 × 5) = 4	Try one alone
42-45 min	Exit check	Three questions marked at once	Finish alone

03 Teaching script (read it out)

Scene 1: Count layers, not formulas

Length 12, breadth 5: one layer holds 12 × 5 = 60 cubes.
Height 4 means 4 layers, so 60 × 4 = 240 cubes, which is 240 cm³.

Student says: “cubes in one layer, times the number of layers”.

Scene 2: A cube is a special cuboid

A cube of edge 6 has length, breadth and height all 6: 6 × 6 × 6 = 216 cm³.
Writing 6³ is just notation, the meaning is the same.

Warn: do not mix it up with surface area, which is six faces.

Scene 3: Litres: 1 L = 1000 cm³

One litre fills a cube of edge 10 cm: 10 × 10 × 10 = 1000 cm³.
So 2.5 L = 2500 cm³, and 0.8 L = 800 cm³.

Student converts one value and explains “multiply by 1000”.

04 Question types and worked steps

Type	Example	Steps	Answer
Cuboid volume	12 × 5 × 4	Multiply all three	240 cm³
Cube volume	edge 6	6 × 6 × 6	216 cm³
Capacity	2.5 L	× 1000	2500 cm³
Backwards	volume 240, base 12 × 5	240 ÷ 60	height 4 cm

Sanity check (teach this): Volume is larger than the base area whenever there is more than one layer; an answer equal to the base area means only one layer was counted.

05 Independent practice (3 questions)

Question	Answer	What to watch
Length 10, breadth 8, height 3	240 cm³	All three dimensions multiplied
Cube of edge 5	125 cm³	Using 5³
A 1.2 L tank holds how many cm³?	1200 cm³	Multiplying by 1000

06 Common mistakes and what to say

Mistake	Student writes	Say this
Only length × breadth	10 × 8 = 80 cm³	That is the base area; multiply by height for the layers.
Units cm²	answer in cm²	Volume is three-dimensional: cm³.
Litres converted wrongly	2.5 L = 250 cm³	1 L is 1000 cm³.
Dividing by one edge	240 ÷ 12	Divide by the base area, not by one side.

07 Homework (paper, section and question numbers)

Primary 5 first-term paper — Section C, questions 10 to 13
Primary 5 second-term paper — Section D, questions 1 to 3

08 Exit check (last 5 minutes)

Question	Answer	Decision
Length 15, breadth 4, height 2	120 cm³	All right: move to decimals
Volume 180, base 6 × 5: height?	6 cm	One wrong: re-teach the backwards step
3 L in cm³	3000 cm³	Two wrong: repeat scene 3

09 Tutor FAQ

Do you teach surface area here?

No. Surface area comes in Primary 6 so the two formulas do not collide.

Students forget the height.

Ask them to write “base area = …, layers = …” before calculating.

Is the pouring experiment worth it?

Yes for 1 L = 1000 cm³; doing it once beats explaining it three times.

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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.