Introduction

Introduce children to subtraction as difference, the third and final subtraction structure; review consecutive numbers, as well as consecutive odd/even numbers, in the context of difference.

Teaching points

• Teaching point 1: Difference compares the number of objects in one set with the number of objects in another set; or the difference between two measures.
   
• Teaching point 2: Difference is one of the structures of subtraction.
   
• Teaching point 3: Consecutive whole numbers have a difference of one; consecutive odd/even numbers have a difference of two.
   
• Teaching point 4: We can apply the structure of difference to compare data.