• Mastery PD Materials

## Additive structures: introduction to augmentation and reduction

Spine 1: Number, Addition and Subtraction – Topic 1.6

### 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.

• Primary
• KS1
• Year 1