Using data from a table to answer comparison problems: how many more...

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Objective

SWBAT solve comparison problems using data from a table

Big Idea

Students use data from a table to solve "how many more" comparison problems. Students identify, use, and share their own strategies for solving comparison problems.

Introduction/Hook

5 minutes

I hand students a handful of colorful candy (jelly beans, skittles, m&ms) or colorful cubes.   I want you to divide your candy (or cubes) by color.  Then we're going to record how much of each color we have on our table.

 After giving students time to separate and count, we tally the amounts as a group and record the results on an anchor chart:

Color

Number of candies (or cubes)

Green

 

Pink

 

Blue

 

Yellow

 

Red

 

 

I start my lesson with this activity since it provides a framework so students can understand how we turn raw data (a pile of colorful candy or cubes) into an organized table.  This activity should be short and the emphasis should be less on counting  and more on reasoning how disorganized data can be organized. 

Introduction to New Material

10 minutes

Now that we have gathered our data, we are going to use this data to tell us important things about the kinds of candy that we have in our class. 

My first question is:  How many extra [Red] than [Yellow] candies are there?  

I allow students to go back to their desks and use manipulatives (cubes and place value blocks) as well as their white board to solve this problem in what ever way see fit.  Students strategies will likely range from concrete to abstract. Some students might solve the problem very concretely by lining up cubes and counting to see how many extra [red] candies there are.  Others might draw bars or circles for both the [red] and [yellow] candies and line them up and determine how many extra there are.  Others might be able to abstractly think about the numbers in the table and set up an appropriate number sentence (MP2). 

In this video, the student draws circles to represent the number of red candies and then shades in the number of yellow candies to determine how many extra (or how many more) there are. 

After students have worked for 3-5 minutes I ask two-three students to share the strategy that they intend to use.  Record strategies on the board as students share them.  As I record the strategies on the board, I make drawings so that students can easily see what each strategy looks like. 

Once students have completed sharing their strategies, I ask them to turn to their partner.

Turn and talk:  What number sentence matches your strategy? 

As students discuss, I circulate to listen to students' strategies and how they are justifying their work.

Some students may set this up as a subtraction problem as [Red] – [Yellow}= _______.  Others might set it up as an addition problem:  Yellow + ___________= Red.  Others might set it up as Red- ___________= Yellow.   It is fine if the number sentences are variable as long as they match the students' strategies. 

 After students have had 1-2 minutes to discuss, I ask two or three students to share out their number sentence and their strategy, showing how their number sentence links to their strategy. 

Guided Practice

10 minutes
Now that we have worked together on a problem, you are going to work in partners on a practice problem.  You can use cubes, place value blocks, or you can make a drawing.  Use the strategies that we recorded on the board to help you.
As students work, I circulate to check for understanding and ask guiding questions:

1) What strategy are you using?
2) Can you show me how you solved this problem?
3) What are you doing to make sure your work is accurate?  
When they are done, I call students back together to go over the practice problem--this time  I have new students share their strategies. 

Independent Practice

15 minutes

Independent practice is differentiated. During independent practice, I will circulate, starting with Group A , moving to Group B, and ending with Group C.  During this time I will (1) support students by asking guiding questions like: why did you choose this strategy?  Why did you choose to add?  Why did you choose to subtract?  and (2) Take notes on common trends and necessary re-teaching. 

Group A: In need of intervention:

Group A will work on comparison problems with numbers 10-30.  This group should be encouraged to use cubes in order to concretely compare  the different amounts.  This group has smaller numbers so that they can easily use cubes and more concrete materials to solve these comparison problems. 

Group B: Right on track!

Group B will work on comparison problems with numbers 15-50, using cubes and place value blocks where necessary.  This group will be required to regroup.

Group C: Extension

Group C will work on comparison problems using numbers 15-100 using cubes and place value blocks where necessary.  This group will be required to regroup in their comparison problems. 

Closing

3 minutes

Today we worked on comparing numbers using addition and subtraction strategies.  Who can tell me some of the strategies that we worked on today?  

We review strategies for comparison problems and make a list on the board.

We will continue to work on these strategies over the next couple days.