Making sense of part-whole strategies for addition and subtraction

Yesterday we shared the (draft) materials for the HNP Summary Documents for the rest of First Level.

Over the next few days, we’ll highlight a few of the guidance materials and example activities that are contained within the Summary Documents to help people know what is available and how it can help.

Today we’ll look at the the document:

Addition and Subtraction: Part Whole Strategies Summary Guidance First**/First***

Firstly, it’s important to know that if you are teaching pupils below or above these levels the document is still relevant.

  • For those working with pupils below First**, it is important to know what’s coming next so you can make sense of why certain skills that your pupils are working on are relevant and how they feed into future strategies.
  • For those working with pupils above First***, the strategies that pupils will use to solve addition and subtraction problems are the same, so this document will still help you to make sense of content relevant to Second Level and above.  The difference between First Level and Second Level and above will be related to:
    • The number range the pupils work within.
    • The pupils’ ability to more effectively choose an efficient strategy based on the numbers within a particular problem.  It should be noted though, that there is still an expectation at First Level that they are reflecting on and justifying their choices.
    • The pupils’ greater understanding of the mathematical properties that underpin these strategies and their subsequent application to algebra.

Within the document you’ll find information related to the following areas.

General Guidance which includes:

  • A general look at how to approach pupil understanding of part-whole strategies (although ideas for teaching is covered in more detail in another document).
  • Information about whether pupils need to learn all the strategies!
  • Information about language and making connections.

Jump and Split Strategies

  • Have you ever wondered why your pupils answer problems like this: 63 – 25 with incorrect answers like 42?
    This is explored in the Jump and Split strategies section.

The Part-Whole Strategies:

The part-whole strategies, that pupils might use to solve addition and subtraction problems, are explored in more detail including:

  • Prior knowledge that may be required.Screenshot 2020-08-20 at 15.11.39
  • Common misconceptions.
  • Representations with concrete materials and visual representations that might support understanding.Screenshot 2020-08-20 at 15.13.54.png
  • The mathematical properties that underpin certain strategies.
  • A video example of a pupil using the strategy to solve a problem mentally.
    While most of the videos show examples of number ranges and strategies at First** and First***, this particular video is highlighting an example of a pupil using a strategy to solve a problem in a number range that is more closely related to Second***.


We hope you find the documents useful and we’ll share some more detail about what’s inside some of the other materials over the next week or two.

This entry was posted in Professional Development, Teaching and tagged , , , . Bookmark the permalink.

2 Responses to Making sense of part-whole strategies for addition and subtraction

  1. Pingback: Progression in Number Ranges at First Level | Highland Numeracy Blog

  2. Pingback: Mathematical Properties – What underpins children’s informal strategies? | Highland Numeracy Blog

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