Subtract a pair of 2-digit numbers by finding the difference
Lesson details
Learning outcome
I can subtract a pair of 2-digit numbers by finding the difference.
Key learning points
- When the minuend and subtrahend are close in value, finding the difference can be an efficient strategy for subtraction
- Finding the difference means we count on from the subtrahend or count back from the minuend
- A number line or a bar model can represent finding the difference
Keywords
Minuend - The minuend is the number being subtracted from.
Subtrahend - A subtrahend is a number subtracted from another.
Difference - The difference is the result after subtracting one number from another.
Common misconception
Pupils will often try to use a written method/algorithm which they know gives an accurate answer but don't understand why it works.
Encourage the pupils to be brave and remind them that this is about mental subtraction so, with practice, will be quicker than any written methods.
Teacher tip
This strategy is shown with number lines and jottings but the end goal is for the children be able to do it mentally so try to reduce such supports as quickly as possible.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.What number is represented by these place value counters?
Q2.What number is represented by the base ten blocks?
Q3.Choose the correct symbol to go between the expressions. 7 + 5 ___ 3 + 4
Q4.Choose the correct symbol to go between the expressions. 20 − 3 ___ 12 + 10
Q5.Choose the correct symbol to go between these expressions. 34 − 10 ___ 14 + 10
Q6.Using your understanding of place value, order these numbers from smallest to greatest.
Assessment exit quiz
6 Questions
Q1.Match the numbers with words for the equation 8 − 6 = 2
Minuend
Subtrahend
Difference
Q2.Which of these bar models represents finding the difference?
Q3.Which of these contexts does not involve finding the difference?
Q4.Which of these subtraction expressions can be more efficiently solved by finding the difference?
Q5.67 − 58 =
Q6. = 96 − 89
To help you plan your 3 maths lesson on: Subtract a pair of 2-digit numbers by finding the difference, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 3 maths lesson on: Subtract a pair of 2-digit numbers by finding the difference, 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 2 maths lessons from the Informal and mental strategies for adding and subtracting two 3-digit numbers unit, dive into the full primary maths curriculum, or learn more about lesson planning.