Calculate the difference in different contexts
Lesson details
Learning outcome
I can calculate the difference in different contexts.
Key learning points
- You calculate the difference by counting on from the known part to the whole.
- The difference is the answer to a subtraction calculation.
- The difference is one of the parts that make the whole.
Keywords
Difference - The amount which a number is greater or smaller.
Subtraction - To partition one part from another (the subtrahend from the difference), or to decrease an amount by taking an amount away.
Count on - A mental strategy used to add numbers.
Common misconception
Children think that 'counting on' is used solely as a strategy in addition.
Children should be made aware that the strategy for 'counting on' can be used in addition but is used as a strategy for subtraction in this lesson where we are finding the difference between two numbers close in value.
Teacher tip
Children should be encouraged to only use 'counting on' as a strategy for finding the difference when it is an efficient choice (when the numbers being compared are close in value).
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Which equation has been written to find the difference between 9 and 6?
Q2.9 and 6 have a difference of
Q3.Here, we are finding the difference between…
Q4.How many have we ‘counted on’ on the number line?
Q5.Which pairs of numbers have the same difference of 5?
Q6.If I know the difference between 10 and 6 is 4, working backwards, I also know the difference between ___ and ___ is 4
Assessment exit quiz
6 Questions
Q1.When would we be best to use the ‘counting on’ strategy to find the difference?
Q2.If a book costs £4 and a toy car costs £12, how would we efficiently calculate the difference in price?
Q3. A teddy costs £9 and a toy car costs £12, how would we calculate the difference in price?
Q4.It takes Sofia 4 minutes to walk to school.
It takes Jun 12 minutes to walk to school.
How much longer does it take Jun to walk to school than Sofia? minutes.
Q5.Jacob wants to buy a new pencil case that costs £12 and he has saved £9 so far.
How much more money does Jacob need to save? £
Q6.When playing a game, the difference between Izzy’s score and Lucas’ score is 3, Izzy scored 9 so how many points could Lucas have scored?
To help you plan your 2 maths lesson on: Calculate the difference in different contexts, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 2 maths lesson on: Calculate the difference in different contexts, 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.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 1 maths lessons from the Calculating within 20 unit, dive into the full primary maths curriculum, or learn more about lesson planning.