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# 1.6 Additive structures: introduction to augmentation and reduction

Created on 31 July 2017 by ncetm_administrator
Updated on 26 November 2018 by ncetm_administrator

## Introduction

Introduce children to addition as augmentation, and subtraction as reduction (take away), using a ‘first…, then…, now…’ story representation and abstract notation (+, − and =); explore the inverse nature of the two operations.

## Teaching points

• Teaching point 1: An addition context described by a ‘first…, then…, now…’ story is an example of augmentation. We can link the story to a numerical representation – each number represents something in the story.

• Teaching point 2: A subtraction context described by a ‘first…, then…, now…’ story is an example of reduction. We can link the story to a numerical representation – each number represents something in the story.

• Teaching point 3: Given any two parts of the story we can work out the third part; given any two numbers in the equation we can find the third one.

• Teaching point 4: Addition and subtraction are inverse operations.

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