Primary 6 · Number & Algebra
P6 percentage
In P6, percentage runs backwards. Your child finds the whole from a part and its percentage, and finds a percentage increase or decrease, in word problems about prices, discounts and numbers that change.
- Taught in
- Term 1
- Syllabus
- 2 skills
- Usual slip
- Using the new price
What your child learns in P6 percentage
Two skills, each with what it looks like on a worksheet.
See the syllabus wording
- finding the whole given a part and the percentage
- finding percentage increase/decrease
Finding the whole
Given a part and its percentage, find a small percentage first. If 75% is $45, then 25% is $45 ÷ 3 = $15, so 100% is $60. The whole is always bigger than the part.
Percentage increase and decrease
Divide the change by the ORIGINAL amount, then × 100%. A price rising from $60 to $75 went up by $15, and $15 ÷ $60 × 100% = 25%.
Key facts and formulas
- 30% is $45: find 10%, then 100%10% → 100% →
- Percentage changeExample$40 to $50 → $50 to $40 →
Words to know
- The whole
- The amount that is 100%, usually what there was at first.
- Original
- The amount before any change, discount or increase.
- Discount
- The amount taken off a price.
- Percentage change
- The change divided by the original, then × 100%.
The sentence that costs the mark
A bag costs $60 after a 20% discount. What was the original price?
What the working usually does
20% ofthe $60 after=$72
Treats the $60 as the whole, so adds 20% of $60 back on.
What the question asked
20% ofthe original=$75
The $60 is only 80% of the original, so the whole is bigger.
The two answers sit $3 apart and both look sensible for a discounted bag. The question never says which number is the whole, and that is exactly the thing being tested.
The same P6 percentage question, worked properly
Lah works through it the way she does every question in StudyLah: one step at a time, marking the picture as she goes.
A chess club had 80 members last year and 60 members this year. By what percentage did its membership fall?
- The membership fell from 80 to 60, a drop of 80 − 60 = 20 members.
- Draw last year's 80 members as 4 units of 20. The drop is 1 of those units. Compare it with the 80, not with the 60 left.
- The percentage fall is 20 ÷ 80 × 100% = 25%.
- So the membership fell by 25%.
Every question in StudyLah comes with a walkthrough like this one.
Try it freeTwo quick P6 percentage questions
Try them together, then tap to check.
Question 1
In a crate of fruit, 40% were apples. The crate had 52 apples. How many fruits were in the crate altogether?
Show answer
Answer130. 40% is 52, so 20% is 52 ÷ 2 = 26. The whole crate is 100%, which is 5 × 26 = 130.
Question 2
A lamp that normally costs $90 was sold at a 10% discount. Members got another $18 off after that. What percentage discount did members get in total?
Show answer
Answer30%. 10% of $90 is $9, so the total discount is $9 + $18 = $27. Against the original $90, that is 30%.
Helping at home
How to tell it has clicked
When a percentage question is in front of your child, ask one thing before they start: what is the 100% here?
The answer you want is the thing that came first: the original price, the amount before the change. Pointing at the biggest number printed is the slip.
Try this tonight
At the next sale sign, ask what the item cost before the discount. Not what you would pay. What it was.
It takes twenty seconds. Reaching straight for the number on the tag is the habit worth working on.
Before and after P6 percentage
Builds on
Primary 5 PercentageWrites parts of a whole out of 100
Builds on
Primary 6 RatioSplits a quantity into units
You are here
Primary 6 Percentage
Finds the whole and the percentage change
The methods your child will use here
More in Primary 6
Struggling with the working rather than the topic itself? How to help your child with problem sums
See how your child is doing on this topic
StudyLah marks each step separately, so you can see whether it was the setup or the arithmetic that cost the mark.