Lesson 5

The purpose of this lesson is for students to represent the action of subtraction with objects.

In previous lessons, students represented addition by putting 2 groups of objects together or adding more objects. In this lesson, students represent the action of subtraction with objects. Students take away a number of objects and determine the number of objects remaining. The language of “take away” and “subtract” is introduced by the teacher throughout the lesson. Students are not expected to produce this language in this lesson. The notation “_____ take away _____” is also introduced. Students need time to see and hear the teacher use this language before they can understand expressions “_____ - _____”, which are introduced in a later section.

• Each group of 2 needs 1 connecting cube.

• Gather materials from: 
  • 5-Frames, Stages 1 and 2
  • Roll and Add, Stage 1
  • Math Libs, Stage 1
  • Match Mine, Stage 1

What evidence have students given that they understand the actions of addition and subtraction? What language do they use or associate with each operation?