##
* *Reflection: Problem-based Approaches
Getting Paid for our Work - Section 2: Doing the Math

The task of setting a price, thinking about change from the original price, and figuring out the total amount earned included several complex tasks. (MP1) Students had to first realize that if they charged more than 25 cents they could not afford to buy their own products. In the real world this may not be the most important aspect of price setting, but to second graders this is the deciding factor. They wanted to get change and see how much money they made overall. The concept of the cost of the materials is one that would take another lesson to really make sense out of. Even students who have had lemonade stands just get the materials from mom or dad. I wanted to introduce the idea of how a factory works, and use the math and build the sun catchers for science so I chose not to stress the idea of paying for the materials out of the profit at this time. Discussing cost of materials and price and profit would be a great extension of this lesson for another math block.

Next students had to think about the concept of getting change back. This is often a difficult concept for students. They have seen their parents get change back (although that happens less and less in a world that uses credit and debit cards all the time), but the concept that the price of the item plus the change should equal the amount paid (their quarter) is hard to visualize.

The Common Core standards solving comparison word problems (2OA.A.1) and this task asks students to do that. Adults take making change for granted, but it is a comparison problem that requires students to grasp that 2 different things can be equal.

Finally, students had to find a way to figure out how much money the factory made. I could have kept the money separate and for every quarter paid, given the student the 15 cents in change and put the ten cent profit in a different container so that students could count up by dimes to find the total earned, but I didn't think of that at the time, so students had to do the problem on paper, using their own visual representations and model with math(MP4) to solve it. Students drew tally marks to represent the dimes, some drew dimes, others counted by tens on their fingers.

Students were using what they knew about math today to solve a series of complex problems.

*Understanding the Value of Money*

*Problem-based Approaches: Understanding the Value of Money*

# Getting Paid for our Work

Lesson 1 of 14

## Objective: SWBAT see how money is used to buy and sell items. They will participate in an activity to see how people get money.

## Big Idea: Combining lessons across subject matter brings an authentic feeling to the lesson. Today the lesson brings together science, social studies and math.

*45 minutes*

Students are studying the factory in social studies. Today they will participate in a mock factory experience where they will work on an assembly line, get paid for their work, and then use their pay to buy the items that they helped to create.

Because students are studying sunlight in science, I made the decision that they would make sun catchers in their mock factory assembly line. Before the lesson, I pre-cut pieces of colored cellophane into 1 - 2 inch irregular shapes, purchased clear plastic page protectors in a small size ( 3x5 photograph pages work well for this) and cut paper frames to fit around the sheet protectors.

At the beginning of the lesson I set up the desks in two long lines. I explained to students, "in a factory each person does the same job over and over again. Today you will each do one part of making a sun catcher (I held up a sample I had made). You will repeat your job until there are no more materials. When you have done your job, you will pass the sun catcher to the next person in line. At the end of the line the quality control person will collect the sun catchers and make sure they are done correctly. If they are not, he/she will bring them back to the beginning to correct the mistakes. Are you ready to work in the factory?" I form 2 assembly lines by telling students what job they will have and lining them up in order. The jobs include putting in 2 pieces of one of the 4 colors in the page protector,(4 different people add their colors), taping the frame to the page protector, decorating the frame and packaging the sun catchers to sell.

I remind students, "you may have to wait for your job until the first people have done their jobs, also don't forget that when your job is done and there are no more materials, you will just need to wait until the other end of the line finishes their work."

Students work on the assembly line until all of the materials are used up and the sun catchers are complete.

After the students complete the sun catchers, I pay each student 25 cents for their work. I have chosen a small amount here because I want to be able to find the total money paid for all of the sun catchers at the end of the lesson and if we start with a larger number (students will probably set the price close to the amount paid. I also know that if I give them each a quarter and they set a price less than 25, they will need to make change and this is in range with practice they have had.) I tell students that we would not just get to take the sun catchers home because people in a factory don't just take the items home with them, but have to buy the items just like everyone else. I tell students that we will buy the items after a lunch break.

The separation of the two activities is a good idea. Students feel that they have "worked" in the factory and been paid, and then later they would get to go shopping. This adds a bit of realism to the process of working in a factory and getting paid for the work.

#### Resources

*expand content*

#### Doing the Math

*20 min*

I begin this part of the lesson by telling students that they will need to decide how much to charge for the sun catchers. Students suggest prices and I record them on the board. Students may suggest prices more than 25 cents. They need to present a good reason as to why their price would be fair for the sun catchers (MP3). We discuss why charging more than 25 cents would mean that not everyone would be able to buy their own sun catcher. Students discuss their own reasons and why charging a penny would not be enough to cover the cost of materials.

I do not make it too complicated in terms of discussing how much materials cost and trying to make a profit. I have to remember what is developmentally appropriate for 7 and 8 year olds. I do tell them that if it were a real factory we would need to buy all of the materials to make our sun catchers out of, and then we would sell them and figure our profit. Here I just talk about it in terms of helping students to settle on a fair price to sell each item.

We discuss how much money they made and whether larger prices will allow them to purchase the items. Students have to critique the arguments of their classmates as they decide which price would make the most sense. (MP3) Students agree on a price by voting on the options.

We discuss the selling price and how much money students have to spend. I ask some thought questions: "Will you get change back? Will you have enough money to buy one or more? How much change will you get and how would we figure that out?"

Students try to figure the answers to the questions including what change they would get and write their ideas and reasoning in their math journals. I circulate around to help students with this process.

Next each student is given the chance to purchase a sun catcher and get change back. They must count their change and make sure it is correct.

I close the lesson by asking students to figure out how much money our factory made if we sold all 30 sun catchers at the cost they set. (This encourages them to count by 5s and 10s because they do not yet know multiplication. They count 10 cents 30 times if they set the price at 10 cents each). This asks students to make sense of the problem "if I know the price of one sun catcher, what would be the total for 30 sun catchers." and persevere in solving the problem using a strategy such as a number grid, number line, adding tens and ones, or tens frames to model what they need to find out and then solve the problem (MP1, MP4).

*expand content*

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- UNIT 1: What and Where is Math?
- UNIT 2: Adding and Subtracting the Basics
- UNIT 3: Sensible Numbers
- UNIT 4: Sensible Numbers
- UNIT 5: Everything In Its Place
- UNIT 6: Everything in Its Place
- UNIT 7: Place Value
- UNIT 8: Numbers Have Patterns
- UNIT 9: Fractions
- UNIT 10: Money
- UNIT 11: The Numbers Are Getting Bigger
- UNIT 12: More Complex Numbers and Operations
- UNIT 13: Area, Perimeter and More Measurement
- UNIT 14: Length
- UNIT 15: Geometry
- UNIT 16: Getting Ready to Multiply
- UNIT 17: Getting Better at Addition and Subtraction
- UNIT 18: Strategies That Work

- LESSON 1: Getting Paid for our Work
- LESSON 2: Making Change
- LESSON 3: More Dimes and Dollars
- LESSON 4: It Is About TIme
- LESSON 5: Smiley Face Number Friends
- LESSON 6: Subtracting with Partners of 100
- LESSON 7: Making Change using Partners of One Hundred
- LESSON 8: Comparing Temperatures
- LESSON 9: Smoothing out subtraction
- LESSON 10: Missing Number Equations
- LESSON 11: Time and Money
- LESSON 12: Crossing Over 100
- LESSON 13: Moving Into Thousands
- LESSON 14: Unit 3 Assessment