Subtract 2 or 3-digit numbers using partitioning and bridging a multiple of 10
Lesson details
Learning outcome
I can subtract 2 or 3-digit numbers using partitioning and bridging a multiple of 10
Key learning points
- By looking at the minuend and subtrahend we know if we will have to bridge 10 or 100
- If the ones digit of the subtrahend is greater than the ones digit of the minuend then we will have to bridge through 10
- If the 10s digit of the subtrahend is greater than the 10s digit of the minuend then we will have to bridge through 100
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.
Partition - Partition is the act of splitting an object or value down into smaller parts.
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.How many pentagons are there in this group of polygons?
Q2.What is the product of 2 and 10?
Q3. = 15 − 9
Q4. = 25 − 19
Q5.Which of the following expressions give a difference of six?
Q6.207 − 190 =
Assessment exit quiz
6 Questions
Q1.Which is the correct definition of difference?
Q2.What subtraction equation does this number line represent?
Q3.Find the difference between 270 and 160 using partitioning.
Q4.Find the difference between 430 and 310 using partitioning.
Q5.Find the difference between 540 and 360 using partitioning and bridging.
Q6.Find the difference between 670 and 490 using partitioning and bridging.
To help you plan your 3 maths lesson on: Subtract 2 or 3-digit numbers using partitioning and bridging a multiple of 10, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 3 maths lesson on: Subtract 2 or 3-digit numbers using partitioning and bridging a multiple of 10, 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.