Make efficient use of subtraction strategies including column subtraction
Lesson details
Learning outcome
I can make efficient use of subtraction strategies including column subtraction.
Key learning points
- A mental strategy may be more efficient than a column method
- Look carefully at the numbers in a calculation to decide a method
- Column subtraction might be the most efficient method to use if regrouping is needed
Keywords
Efficient - Being efficient means finding a way to solve a problem quickly whilst also maintaining accuracy.
Mental strategy - A mental strategy is a method chosen to find something out which can be done in your head or with some jottings.
Regrouping - The process of unitising and exchanging between place values is known as regrouping.
Common misconception
Pupils may think that column subtraction is always the most efficient strategy where regrouping is needed.
Emphasise calculations where adjustment is the most efficient strategy (e.g. 456 - 199). Regrouping is needed in both the tens and hundreds, but is is not the most efficient strategy.
Teacher tip
Pupils will need to be familiar with column subtraction using 3-digit numbers, including regrouping in the tens and ones. They will also need some understanding of mental strategies. You may wish to revisit strategies such as rounding and adjusting or partitioning to subtract before the lesson.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Where is regrouping needed in the column subtraction?
Q2.Where is regrouping needed in the column subtraction?
Q3.Finish the column subtraction. What is the difference?
Q4.How would you subtract 99 from 387?
Q5.Calculate 387 − 99 =
Q6.Complete the column subtraction. What is the difference?
Assessment exit quiz
6 Questions
Q1.Which calculations would it be most efficient to answer using a mental strategy?
Q2.Which calculations would it be most efficient to answer using column subtraction?
Q3.Sam calculates 401− 396 by counting on from 396 He found a difference of .
Q4.Aisha wants to calculate 827 − 299 How should she calculate this using a mental strategy?
Q5.What is 555 − 199 = ?
Q6.Calculate 941 − 323 =
To help you plan your 3 maths lesson on: Make efficient use of subtraction strategies including column subtraction, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 3 maths lesson on: Make efficient use of subtraction strategies including column subtraction, 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 Column subtraction unit, dive into the full primary maths curriculum, or learn more about lesson planning.