Two questions, two different wholes, one method. A part turns into a percentage as the part over the whole, times one hundred percent. In the lesson. So name the whole first: whatever amount the question puts after the words percentage of, and here that is all forty-five minutes of the lesson.
Lesson video, with the working
Part as a percentage
4 min 14 s
The film teaches 2 questions in turn. Each question shows first; its working is written as the film explains it.
There are 75 books on a shelf. Of them, 15 are comic books. Express the number of comic books as a percentage of the number of books on the shelf.
Comic books are 20% of the shelf.
Ans: 20%
Example 1
A lesson lasted 45 minutes. 18 minutes of the lesson were spent on practice. Express the time spent on practice as a percentage of the length of the whole lesson.
40% of the whole lesson was practice.
Ans: 40%
How to solve it
Name the whole first: the amount after the words percentage of. Here it is all 75 books, which is one hundred percent.
Write the part over the whole: 15 over 75.
Simplify: 15 and 75 both divide by 15, which leaves 1 over 5, or one fifth.
Multiply by one hundred percent: one fifth of one hundred is 20, so the comic books are 20 percent.
With a new whole of 45 minutes, the part of 18 minutes is 18 over 45, which is two fifths, or 40 percent.
Two questions, two different wholes, one method. A part turns into a percentage as the part over the whole, times one hundred percent.
Practice questions with worked solutions
Question 1 is free to try. The other 9 open in the free trial, each with its full working.
Question 1 of 10 · Basic · free to tryA packet holds 8 sheets of paper. Mei Ling used 3 of the sheets. Express the…A packet holds 8 sheets of…
A packet holds 8 sheets of paper. Mei Ling used 3 of the sheets. Express the number of sheets she used as a percentage of the number of sheets in the packet.
How do you answer express as a percentage questions in P6?
This page teaches one method for any 'what percentage' question: the part over the whole, times 100%.
What your child learns here
This page teaches one method for any 'what percentage' question: the part over the whole, times 100%. The skill was first met a year earlier; here it is applied to wholes that are sums, leftovers and groups of several kinds.
Express a part of a whole as a percentage using part over whole times 100%.
Find the whole by reading what comes after the words 'percentage of'.
Work out the part first when the question asks about the rest or about two kinds together.
Give the final answer with the % sign, not as a decimal or a fraction.
Does the answer make sense?
Each answer is a part of its whole, so it must lie between 0% and 100%. Your child's answer should sit below 50% exactly when the part is less than half the whole: 18 minutes out of a 45-minute lesson is under half, so the percentage of practice time must be under 50%.
How to practise these questions
The Basic questions train writing one quantity as a percentage of another. Intermediate questions add finding the part that remains first. Challenge questions use a whole that is a sum, how far short of a goal something falls, or a pie chart sector to read before finding a percentage. When part-as-a-percentage stalls, read the written step-by-step solution together.
Questions parents ask
What is the formula for expressing as a percentage? Part over whole, times 100%. The whole is whatever comes after the words 'percentage of' in the question.
Should the answer be a decimal or a percentage? If the question asks what percentage, the answer is written with the % sign. A decimal such as 0.85 shows the same value, but it is not in the form asked for.
Is expressing as a percentage taught in Primary 6? It is first taught the year before, as expressing a part of a whole as a percentage. In Primary 6 it comes back inside longer word problems, where finding the part or the whole is a step of its own.
