1. Problem Structures: Comparing
Unit of Study: Addition and Subtractions Concepts
Global Concept Guide: 3 of 5

2. Content Development
Students will work through the three day GCG on the problem structure comparing.
Why are comparison problems so difficult for the students?
“Compare problems involve the comparison of two quantities. The third amount does not actually exists but is the difference between the two amounts.” (Van De Walle, p. 147)

3. Content Development 6 - 4 = 6 = 4 +
“Comparison situations differ from taking from and taking apart situations in that they involve only two discrete quantities that are not parts of a whole or related in that way..” GO Math Chapter 2 TE, pg. 73A
The terms “more”, “less” and “fewer” when used to compare can create confusion. Students generally can identify who has more, but do not recognize how many more. Students need experience with both terms.
Take the opportunity to expose students to addition sentences with missing addends as related to the problems.
6 - 4 = 6 = 4 +

4. Day 1
Essential Question: How can you use manipulatives to compare two numbers?
Day 1 focuses on having students use snap cubes to build number trains and compare quantities.
Session 8: Compare Problems (Difference Unknown)- Children represent and solve add--‐to and take--‐from problems where the result is unknown using linking cubes to represent the situation and then compose or decompose the number sentence.
Third number is not really there, but rather the difference
Illuminations- Comparing Connecting Cubes - model a subtraction problem in which two sets are compared and write the equation to match.
It is necessary for students to physically place number trains side by side and count the difference.
By the end of Day 1, students should be able to use manipulatives to compare two numbers.

5. Day 2 How can you use pictures and models to compare two numbers?
Go Math Lesson 2.5 & 2.6-Use both lessons to compare two numbers.
After working with manipulatives on day 1, students will work with picture representations of the problem on the second day.
Allow students to continue the use of manipulatives to model if needed, but encourage them to draw quick models (i.e. circles, tallies, etc.) to assist.
It is essential for students to see that the numerical answer can be the same for a problem whether being asked how many more or how many less, but the answer represents a different part of the problem.
By the end of Day 2, students will be able to draw pictures and models to compare two numbers?
Snap Cubes
Quick Picture

6. Day 3 How can we use different strategies to compare two numbers?
Voyages 1st Grade Excursions: Compare Probe students and facilitate the discussion that the models created with manipulatives are directly related to the bar model. Number lines and snap cubes can help clarify this.
Differentiate the problems given to students based on needs. For example, #4 on page 75 might be more appropriate for a below level student, where as #5 could challenge your on level and above level students.
By the end of Day 3, students will be able to use multiple strategies to compare two numbers.
The performance task will be administered in the second half of this day.
Great discussion starter:
How does the snap cube model compare to the bar model?

7. Enrich/Reteach/Intervention
P. 69B TE - Create compare story problems
Create index cards for matching scenarios with equations and representations (including missing addends)
Reteach
Grab and Go Center Big Idea 1: Activity 16 – Placing counters in a cup and comparing red/yellow
Grab and Go Center Big Idea 1: Activity 17 – Partner cube compare with dice
Connect to pictures and making a model.
P. 73B RtI Tier 2 – Walks through reteach with comparison
Intervention/Small Group
GO Math Grade 1 Chapter 2 TE - RtI Tier 2 Activities pages 69B and 73B
GO Math Grade 1Rti Strategic Intervention Guide – Skill 12