Lesson: Total Cost: Given the Unit Cost
SWBAT solve for the total cost when given the unit cost
Materials Needed: DN worksheet, a CD for a visual aide, GP worksheet, IND worksheet
Vocabulary: unit, cost, multiplication, total
Do Now (2 - 3 min): Teacher gives each student a copy of their DN Worksheet and asks them to complete the work quietly.
Opening (2 -3 min): Teacher reviews the DN Worksheet. Teacher says, “Today, I am going to need you to put on your critical thinking hats and remember when we talked about money and cost earlier in the year. Today we are going to combine a lot of information that you are already familiar with in order to learn a new skill. By the end of the lesson today, you will be able to solve a problem to find the total cost.”
Direct Instruction (10 - 12 min): Teacher holds up a CD and says, “We all know what this is, but who can tell me what it usually costs? [Answers will vary] Ok, I heard several different answers, and the truth is that it will cost different amounts depending on where you buy it. Today we are going to talk about how much something like a CD would cost if we buy a lot of the same thing. If I bought this one CD, it might cost me $10, but if I bought 100 of this CD, then the person or company selling the CD to me might only charge me $8 per CD. Why do you think this could be true, why would I get charged less for buying more? [Answers will vary] Ok, I heard a lot of good answers. The truth is, companies and even people want us to buy more so that they can sell more quickly and easily. Companies will give a unit cost if you agree to buy a large amount of an item. A unit cost is a special cost for an item that you are going to buy more than one of.” Unit costs are all around us, even in a grocery store. If I buy one apple, it might cost me seventy-five cents, but if I buy a bag of 10 apples, it might cost me 3 dollars, which makes the unit cost of those apples 30 cents instead of 75 cents.”
Teacher continues, “I don’t expect you to completely understand how the world economy works right now! However, I do want you to remember two things!” Teacher writes on the board:
Unit cost= special cost because you are buying more than one of something
Teacher says, “Today, we are going to calculate the total cost if we are given the unit cost of something. Tomorrow we will work on finding the unit cost if we are given the total cost. Now, I said I want you to remember two things, the first is the definition of a unit cost, and the second is that we always use multiplication when we are finding the total cost of something. We will multiply the cost by the amount of the item we want to buy.” Teacher writes the following on the board:
The unit cost of a CD is $8, how much will you spend if you buy 100 CDs at this cost?
Teacher says, “If I have a problem like this, I want to set up a mathematical equation that will help me solve the problem. This problem says that a CD cost $8 (teacher writes 8 on the board) and I am buying 100 CDs (teacher writes 100 on the board). What operation did I say we use when we are calculating the total? [Multiplication] Very good! So I will multiply 8x100 and this equals 800. So I know that it will cost $800 to buy 100 CDs that cost $8 each. Now, I want you all to try to calculate the total cost of certain items in small groups. I will give you a worksheet with three problems on it, and I want you all to solve those three problems together. When you are finished, I will review them with you before I ask you to practice on your own.”
Guided Practice (10 -12 min): Teacher gives each math group a GP worksheet and circulates the room to answer any questions. When most students are finished, the teacher reviews the answers to each problem on the board, making sure to highlight the definition of a unit cost, and that you must multiply to find the total cost.
Independent Practice (10 min): The teacher hands out the IND Practice worksheet. Students are asked to complete the worksheet independently and turn it in.
Closing (2-3 min): Teacher calls the attention of the students back toward the front of the class to quickly review the answers to the Independent Practice worksheet/ ask what we learned about.
|GP lesson 5 unit cost Classwork||
|DN lesson 5 unit cost Starter / Do Now||
|IND lesson 5 unit cost Classwork||