Cheerful Shoppers

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Objective

SWBAT to justify addition and subtraction of two- and three-digit whole numbers with and without regrouping using money.

Big Idea

Students love to shop! Students will use their own shopping list to compose a word problem using addition and subtraction with and without regrouping, in order to help them better understand how to problem solve.

Gathering the Info

10 minutes

Teacher's Model In this exciting lesson on how to make change, I want students to be able to compare different multiplication situations to understand how a given quantity is multiplied by a specific number to get another number.

 Things you will need

I give students a set amount of money and change to purchase items from a classroom generated store.  This will give students a clearer view on how change is generated in a real-world scenario. 

Required Skills:

addition, subtraction, reasoning, counting money up to $5.00, and basic number sense. 

After that, I tell students that my goal by the end of this lesson is for them to be able to identify and verbalize which quantity is being multiplied and which number tells how many times. 

 Student/Teacher Discussion:

I model a variety of problem solving techniques to engage the students.  I make sure to encourage students to offer up solutions to the given problem.  MP1-Make sense of problems and persevering in solving them.

First, I used a Math Model to demonstrate how to generate and answer higher order thinking questions when solving math problems. 

Teacher: Do you understand what the problem is asking you to do? (If so state the problem.)

Students:

The problem is asking us to tell how much money Ben has left.

Teacher: How much money did Ben have already?

Students

Ben had....... 

Teacher:  How much did Ben pay for the pack of pencils?

Students:

Ben paid.....

Teacher: How do you calculate (addition or subtraction) this word problem?

Students:

Because the question asked how much did Ben have left. Have left is the clue word.

Teacher:  Can you think of another way to solve this problem?

Students/Teacher:

Wow. I had numerous ways explained, and some of them were pretty good!

I may continue probing students until they can answer mathematically on their own. 

I encourage students who seem to struggle to use play money.

We will use the following Mathematical Practices in this lesson: 


MP.1. Make sense of problems and persevere in solving them.

MP.2. Reason abstractly and quantitatively.
MP.3. Construct viable arguments and critique the reasoning of others.
MP.4. Model with mathematics.
MP.5. Use appropriate tools strategically.
MP.8. Look for and express regularity in repeated reasoning. 


Rattling the Coins

15 minutes

I ask students to move to their assigned  groups. I encourage them to work collaboratively solving Money Word Problems Practice.docx

  I explain that I am going to model how they should be thinking and talking as they work together solving problems. I want students to be able to explain their thinking to the problem they are solving.

MP3-Construct viable arguments and critiquing the reasoning of others.

Method Steps:

Circle the numbers: Students circle the numbers being added or subtracted.

Underline important words: Students circle important words.

Box the question: Students draw a box around the questions that they need additional support on. It allows the students to continue working, focusing on what they can do, and it helps the teacher better understand students weakness. I may ask how did you reach that conclusion?,. Does this make sense? Why is that true?

Eliminate unnecessary information: Great testing strategy that allows students a better chance in choosing the correct answers during assessments.

Let me give you an example of what students work should look like:

Mr. Johnson's class has 21 students. If the seven of his students are absent due to heavy rainfall on a particular day, how many students does he have left in his class on that day?

 

Over the years I have seen several different age groups of elementary students use this method with great success. As students get older, it becomes unnecessary for them to do each of these steps.  However, it begins the process that is needed for them to become successful problem-solvers.

Checking for understanding

At this stage of the lesson I basically joined in as needed to correct any misconceptions.  However, I continued to ask students questions that focused on why/how they solved their answers! 

Student Work-Sample

Dispensing the Change

20 minutes

Shopping Lists:shopping list2.pdf  wish list.pdf

To Begin:

During this part of the lesson students are prompted to move back to their seat to work independently, creating a shopping list using cut outs from the local grocery store flyer. shopping lists

 However, it is more creative for students to create their own.  As students work, I circle the room to ask them to explain how they solve their problem.

Students Chat

Students are pretty much finished with their creative math piece, and are eager to share their results.  I gather the students in a whole group setting with a “big chair” sitting in the middle of the circle we made.  The chair is used for the student volunteers that are willing to share and explain their work. 

I start off by saying, “I really saw some awesome mathematical practices being used!” 

I remind students that applying skills in steps until they fully understand how and why they work is important. I say, it is also important that we learn to share and discuss various ways we solve problems. At this point students are really communicating those higher order thinking responses I talked about in “gathering info section” of this lesson.  

Assessing Student Thinking

While students are sharing their work I take anecdotal notes to discuss later with each student. These notes can also be used as a running record of the student’s progress along the way, and reference for keeping parents informed. I use this practice to establish a strong school/home connection. For instance, I ask students how and why questions to determine if they can explain on their own. Some students are able to explain, however, their explanations are vague.

This closing piece was exceptional and reinforced the key mathematical practices described in Common Core. 

The link below is for additional practice for students who finish early:

Online Resource