Reflection: Rigor The Story of Multiplication Day 2  Section 3: Poster Revision
This type of activity can feel very loose, as you are allowing students to roam around and try to focus on the work, we as teachers try so hard to see. It may seem impossible, but if you are careful to set up the prompts and work to have a safe environment where everything is up for discussion, this can be the most powerful moment of your lesson.
I was so impressed with the students' perseverance and stamina in struggling to make meaning of the work. They had to really work to understand each other's strategies  rather than being told the strategy. To discover each other's thinking, they had to determine what and how to comment, and then comment in a way that would be helpful to their peers. As we all know, when we work to explain, we dig deeper into our own understanding.
Don't expect perfection, but with time, this will be a natural part of a student's learning.
The Story of Multiplication Day 2
Lesson 11 of 15
Objective: Students will be able to evaluate peermade multiplication problems with display and critique, offer comments, and suggestions to one another.
Big Idea: In the second day of a two day lesson students work on expressing multiplication in various ways, and also work to develop their math communication and critiquing skills.
Warm Up
Yesterday, students wrote their own multiplication story (word problem) and then modeled the math two to three other ways. Today, students poster tour their peer's work from yesterday. Prior to setting them off on a tour, I put up a poster of my own work, with a misconception and a well constructed word story with the factors misplaced.
I then ask the students to view my work and discuss with their partner what they notice. Before they share out, I put up three sentence starters to guide thinking. I then ask students to phrase their comments using these starters. For today's lesson, the prompts are:
 I understand your equal groups because...
 I disagree with_________because...
 Maybe you could show your math by using this strategy....
Poster Tour
As the students rotate around the room in partnerships, they are instructed to respond to each other using talking moves and to the work using the sentence prompts. This keeps the conversations focused on the math and not opinions.
In the previous lesson, the students were asked to multiply a 1 digit by 1 digit number obtained from rolling two dice. Their instructions were to write at least one word problem and then use other models. I listened and watched for the following types:

groups of represented by arrays, drawings

repeated addition on a number line
Strategies can include use of what is known to determine what is unknown (e.g., I know that 2 x 2 is 4 so I know that 4 x 4 would be double the product because 4 is double the multiplicand/multiplier (not that we expect them to use this language).
At each poster, there is a chart with the sentence prompts and a pad of sticky notes. The students will use the note to write their comment and then will place them in the column with the appropriate sentence starter heading.
If you have not worked with talking moves yet, or sentence prompts, try using one at a time until your students are used to using them. Both of these build life long communication and thinking skills, and are appropriate as minilessons.
This activity is appropriate for all styles of learners, as you will see in this video.
These students work together to not only give feedback, but to make sense of "what doesn't make sense".
Resources (1)
Resources (1)
Resources
Poster Revision
Revision is one of the most powerful teaching tools we can use. Our work is no longer incorrect, it is thinking we can safely change to reflect a change in our understanding.
In order to practice revising their thinking, the students return to their work and read over the comments and suggestions left by the visiting mathematicians. This is heavy work. It takes a safe working environment for students to get feedback from each other and value that input, rather than it coming from the teacher. It is, as well, much more powerful. As the children decipher the comments, they can begin to revise their work and add to it any strategies they saw from their own touring.
This is an effective, and an important, math practice. However, be prepared for the noise level to increase as the debates to begin. Remember, it may be noise, but when its accountable talk, huge growth is happening.
The students here are beginning a conversation about how the suggested revision made them think of multiplication as it relates to division. Listen to the natural and spontaneous dialogue regarding this issue with the whole class. This is what we are looking for in a math community!
Wrap Up
After several minutes of debate and revision, I give the students time to share one thing from their poster with the whole group. If you don’t have time for that, another model is to have two groups merge and share with each other.
While the share is happening, I listen in, model questioning such as, “Why did you choose to do it that way?" Or, “How did you know to make it 9 groups of 3 and not 3 groups of 9?” As we progress, students will be asking each other these types of questions.
For home practice, I assign a number story by rolling the dice and ask the students to represent it with a word story and 2 other ways.
Similar Lessons
African Amphibians  Review Multiplying by Ones & Twos While Learning Fun Facts About Frogs
Environment: Urban
Multiplication Models and Structure
Environment: Urban
Environment: Urban
 UNIT 1: Developing Mathematical Practices
 UNIT 2: Understanding Multiplication
 UNIT 3: Using Multiplication to Find Area
 UNIT 4: Understanding Division
 UNIT 5: Introduction To Fractions
 UNIT 6: Unit Fractions
 UNIT 7: Fractions: More Than A Whole
 UNIT 8: Comparing Fractions
 UNIT 9: Place Value
 UNIT 10: Fluency to Automoticity
 UNIT 11: Going Batty Over Measurement and Geometry
 UNIT 12: Review Activities
 LESSON 1: It's As Basic As That
 LESSON 2: Naming Arrays
 LESSON 3: Variables
 LESSON 4: X Represents Groups Of
 LESSON 5: Each Orange Had 8 Slices
 LESSON 6: Creating a Word Problem Book
 LESSON 7: Equal Groups on a Number Line
 LESSON 8: Collections of Equal Groups
 LESSON 9: Explaining Multiplication
 LESSON 10: The Story Of Multiplication Day 1
 LESSON 11: The Story of Multiplication Day 2
 LESSON 12: Making Equal Groups Part 1
 LESSON 13: Making Equal Groups Part 2
 LESSON 14: Associative Property
 LESSON 15: Associative Property With Manipulatives