Lesson 4

More Work with 1 and 2

Lesson Purpose

The purpose of this lesson is for students to subtract 1 or 2 within 10.

Lesson Narrative

This builds on the previous lesson where students considered the number sequence to support them in adding 1 or 2. When students see that subtracting 1 or 2 from any number is the same as counting one or two less, or counting back one or two, they are observing an important structure of the count sequence (MP7, MP8).

Math Community

Tell students that, at the end of the lesson, they will be asked to identify specific actions from their “Doing Math” list (both teacher and student sections) they personally experienced during the lesson today.

• Representation
• MLR8

Learning Goals

Teacher Facing

• Subtract within 10, given expressions in which 1 or 2 is subtracted, in a way that makes sense to them.

Student Facing

• Let’s subtract 1 or 2.

Required Preparation

Activity 1:

• Each group of 2 needs a set of number cards 0–10.

• Each group of 2 needs a Five in a Row game board from the previous lesson.

Activity 2:

Gather materials from:
• Counting Collections, Stage 1
• Number Race, Stage 3
• Check it Off, Stage 1
• Five in a Row: Addition and Subtraction, Stages 1 and 2

Building On

Lesson Timeline

 Warm-up 10 min Activity 1 20 min Activity 2 20 min Lesson Synthesis 10 min Cool-down 0 min

Teacher Reflection Questions

What strategy did most students use in their work today? What surprised you about student thinking?