Primary 6 Maths: Percentage Applications — Tutor Lesson Plan (increase, decrease, discount)

2026-10-27

Tutor lesson-prep guides · Primary maths

Every percentage question has one key: what counts as 100%. Students who name the base first stop making sign and division errors.

Objectives — the student can name the base amount, compute an increase, a decrease and a discount, find the original price from a sale price, and use a single multiplier.

01 Prerequisites (3-minute check)

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

Skill	Quick check	Pass mark
Meaning of percent	What is 25%?	25 out of 100, or 0.25
Fraction to percent	3/4 as a percentage	75%
Multiplication	480 × 0.25	120

02 Lesson flow (50 minutes)

Time	Stage	Tutor does	Student does
0-6 min	Name the base	Ask “10% more of what?”	Answer: of the original price
6-16 min	Find a percentage	Show 25% of 480	Two alone
16-28 min	Increase and decrease	80 plus 15%, 60 minus 25%	One each
28-38 min	Original price	Sale price 85 at 20% off	One alone
38-46 min	Fix errors	Board “up 20% then down 20%”	Explain why it does not return
46-50 min	Exit check	Three questions marked at once	Finish alone

03 Teaching script (read it out)

Scene 1: What is the 100%?

“10% more” means 10% of the original, so the original is 100% and the new price is 110%.
Write the base amount before touching the calculator.

Student answers that a discount is a percentage of the original price.

Scene 2: One multiplier beats two steps

80 increased by 15% is 80 × 1.15 = 92.
Two steps also work, 80 + 12, but one multiplication has fewer places to slip.

Student does 120 × 0.85 = 102.

Scene 3: Original price: divide, do not add

Sale price 85 at 20% off means original × 0.8 = 85, so original = 85 ÷ 0.8 = 106.25.
Adding 20% to 85 gives a different number.

Warn: up 20% then down 20% does not return to the start, because the second base changed.

04 Question types and worked steps

Type	Example	Steps	Answer
Percentage of	25% of 480	480 × 0.25	120
Increase	80 plus 15%	80 × 1.15	92
Decrease or discount	60 minus 25%	60 × 0.75	45
Original price	85 after 20% off	85 ÷ 0.8	106.25

Sanity check (teach this): An increase always ends above the original and a discount always below; a discount price higher than the original means the division used the wrong multiplier.

05 Independent practice (3 questions)

Question	Answer	What to watch
40% of 250	100	Converting to 0.4
120 minus 15%	102	Using 0.85 in one step
50 raised to 60: percentage increase	20%	Base is 50

06 Common mistakes and what to say

Mistake	Student writes	Say this
Wrong base	using the sale price as 100%	A discount is a percentage of the original.
Adding the percentage as a number	80 plus 15% written as 80 + 15	15% of 80 is 12, not 15.
Adding to reverse a discount	85 at 20% off becomes 85 + 17	Divide by 0.8 instead.
Assuming percentages cancel	up 20% then down 20% returns to the start	The base changes, so the result is 4% lower.

07 Homework (paper, section and question numbers)

Primary 6 first-term paper — Section E, questions 1 to 4
Primary 6 first-term paper — Section D, questions 1 to 3

08 Exit check (last 5 minutes)

Question	Answer	Decision
40% of 250	100	All right: move to circle area
120 minus 15%	102	One wrong: re-teach the base
Percentage increase from 50 to 60	20%	Two wrong: repeat scene 1

09 Tutor FAQ

Should they use ×1.15?

Yes in Primary 6, but keep the two-step version alive so the meaning is clear.

Discounts in a separate lesson?

No, a discount is just a decrease; one lesson reduces confusion.

Interest and tax?

Not required at this level.

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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.