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# Progression in Subtraction

Created on 13 March 2013 by ncetm_administrator
Updated on 30 June 2014 by ncetm_administrator

# Progression in Subtraction

## Introduction

This suite of videos looks at elements of progression in subtraction in Key Stage 2. Julie, in Lower Key Stage 2, explores partitioning and how this links to exchange in the decomposition method for subtraction. Danielle, in Upper Key Stage 2, successfully introduces the compact algorithm.

## Partitioning

This video can also be watched on Vimeo, the video hosting site, where it is also possible to download a copy for your own use.

## Discussing Subtraction Strategies

This video can also be watched on Vimeo, the video hosting site, where it is also possible to download a copy for your own use.

## Developing Column Subtraction

This video can also be watched on Vimeo, the video hosting site, where it is also possible to download a copy for your own use.

## Column Subtraction

This video can also be watched on Vimeo, the video hosting site, where it is also possible to download a copy for your own use.

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19 May 2016 15:26
When discussing different strategies which can be used for subtraction, mistakes can be a valuable platform to increase the learning of the child, and this is because it allows them to find the strategy which works best for them, as well as the one they find easiest to complete the problem.
13 October 2015 08:40
I've used these videos to demonstrate how trainees on our PGCE programme should be working with small groups in mathematics. The strong modelling element is particularly useful.
23 May 2014 17:49
I also wondered about having the column headings H T and U and then saying the quantity value for a number rather than the column value. If the number is 152 then there is 1 hundred, 5 tens and 2 ones which they see from their counters. I think this is a very useful video but there are still points for discussion.
09 April 2014 17:23
I have introduced that method in primary school once they can perform basic calculations with negative numbers. The children thought it was fantastic! Perhaps we should introduce negative numbers earlier in the primary school syllabus?
09 April 2014 17:00
Does anyone recommend the method of column subtraction where you do take a larger number from a smaller number to give a negative number? You do each column in turn getting a positive or negative answer then add or subtract the results from each column to get the final answer. I saw the method on teachers TV and thought it very straight forward.
09 April 2014 14:31
If you continue to watch the video, you will see children commenting that you can't take away ( a larger number from a smaller number) without getting a negative number, demonstrating they understood this. However in the context of the algorithm this is a constraint, where taking away a larger number from a smaller number is dealt with in a particular way through exchange. Using the correct language is if course important, however we all make the odd slip up, or we decide not to address it at that point in time. The videos are not intended to represent perfection, I am sure you will agree no lesson is perfect and there are a lot of good things in this lesson. Thank you for your comment, correct mathematical language is important.
09 April 2014 13:57
I think it is important to encourage correct mathematical ideas through correct language. " five takeaway eight we cannot do" is just not correct ! We might not fancy doing it because it involves negative numbers, but it certainly can be done. What does the teacher say to these kids when they are asked to do " five takeaway eight" ?
01 April 2014 20:19
Thank you Barbara and best wishes for a speedy recovery
01 April 2014 18:00
This is exactly what we need! Clearly staged approaches that build on conceptual understanding, using practical equipment, discussion, expanded methods to make value of each partitioned section leading to discussion about what is the same and what is different about expanded and compact methods. Thank you. Ps watching this in my hospital bed after an operation so it must be worth watching!!!!
28 February 2014 07:24
The section on number and place value contains a video called "partitioning". This has a focus on addition and subtraction