Myths about teaching can hold you back
- Year 6
Explain how to solve problems where the percentage part and size is known but the whole is unknown
I can solve problems where a percentage part is known but the whole is unknown.
- Year 6
Explain how to solve problems where the percentage part and size is known but the whole is unknown
I can solve problems where a percentage part is known but the whole is unknown.
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Lesson details
Key learning points
- If I know about a part, I can work out the whole from that part.
- If I know what 10% is, I can multiply by 10 to calculate 100%.
- If the part is a factor of 100, I can multiply the part by the other factor to calculate the whole.
Keywords
Percentage - A percentage is a proportion of a whole.
Common misconception
Pupils may not always instantly recognise that a percentage part is a factor of 100
Discuss factors of 100 with the pupils, for example, as factor pairs. Allow them to keep these displayed to refer to throughout the lesson if needed to help make this connection.
To help you plan your year 6 maths lesson on: Explain how to solve problems where the percentage part and size is known but the whole is unknown, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 6 maths lesson on: Explain how to solve problems where the percentage part and size is known but the whole is unknown, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
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Explore more key stage 2 maths lessons from the Understanding percentages unit, dive into the full primary maths curriculum, or learn more about lesson planning.
Licence
Prior knowledge starter quiz
6 Questions
Q1.If 100% of an amount is 320 km, find these percentages.
160 km
32 km
3.2 km
80 km
240 km
Q2.10% of a race is 1.5 km Calculate these percentages of the race.
3 km
4.5 km
9 km
0.75 km
12 km
Q3.Aisha’s battery has 61% of 600 minutes left. Complete each step of the table to calculate 61% of 600 minutes. minutes

Q4.Lucas needs to find the number of children who cycled to school. Look at the pie chart and complete each step of the table to calculate 21% of 400 children

Q5.Look at the table and find the missing percentage. 18 = % of 60

Q6.Use the table to calculate the missing percentage. 440 = % of 800

Assessment exit quiz
6 Questions
Q1.If I know a part, I can work out the whole. Match the parts of the sentence correctly.
I can multiply by 10 to calculate 100%
I can multiply by 4 to calculate 100%
I can multiply by 2 to calculate 100%
I can multiply by 5 to calculate 100%
Q2.Lucas has read 25% of his book. He has read 64 pages. His book is pages long.

Q3.Aisha thinks of a number. 20% of her number is 104 What is her number?
Q4.Lucas has read 75% of his book. This is 90 pages. How many pages are in his book? pages

Q5.Aisha thinks of a number. 40% of her number is 72 What number is Aisha thinking of?
