Counting up the Cost!
Lesson 15 of 15
Objective: 4.NBT.4 Students will be able to add and subtract a collection of coins.
Preparing for the count!
The purpose of this lesson is to help my students explore different ways to add and subtract coins. Although money is not specifically mentioned in fourth grade “Common Core”, students should use methods they can explain and understand. As with addition and subtraction, students are expected to use previously taught skills such as; arrays, diagrams, and money. These visual representation help students visually draw and connect to equations and other written numerical work.
Materials: play coins or real coins (dollars, quarters, dimes, nickels, and pennies)
To start, I invite students to the carpet to review the worth of dollars, quarters, dimes, nickels, and pennies. I give each student 2 dollars, 2 quarters, 2 dimes 2 nickels, and 2 pennies. I ask students to place 2 quarters, 1 dime, 1 nickel, and 2 pennies in a row. I draw the money on the board. I ask students, what is the total value of money? $2.82 Can anyone tell me how I would write this amount? You need to write two dollars and eighty two cents. Great! I repeat this activity about two or three more times just to make sure students understand how to count a collection of money. I point to the money written on the board, I ask students what side of the decimal is the cents written on. It is written on the right side. However, I do not probe heavily in this portion of the lesson, because I am merely checking for understanding. I will probe a bit more as students move deeper into the lesson.
MP.2. Reason abstractly and quantitatively.
MP.4. Model with mathematics.
MP. 8. Look for and express regularity in repeated reasoning.
How do I determine the Cost?
Materials: Activity One.docx
Some of my students are use to counting money, however, in fourth grade, the difference is the students will have to mentally solve the problems as if they were in the real world. This begins the teachings of finances and help students understand the value of money. I want to make sure that my students do not get confused by the decimal point in the dollar and cents notation. To quickly correct this before the activity begins, I point out to students that the decimal point separates the dollars and the cents amount in money. I tell them it is easier to understand if you count the dollar amount first. Some students ask why. When writing money the dollar amount comes first. I may use a place value chart at this point, so that students can make the connection. I ask students to note the value of the digit on the let and right side of the decimal. Students quickly make the connection when compare to the numbers place value.
I write $5.24; $7.98; $23.56; $56.79 on the board and I ask students to copy them into their math pads. Can any one tell or show me how to write this amount($5.24) in words? I give them about five minutes or so to turn and talk with their neighbor. Some students gave different examples of how to write $5.24 five dollars and twenty four cents: five dollar bills, two dimes, and four pennies.
For example, I write certain money values on the front board and ask the students to copy them into their notebooks. Then I ask them to write, in words, the different ways the one value can be achieved. The value $4.28 is written on the board. I give the students five minutes, individually at their seats to answer this problem. I asks the class for participation and write all the answers on the board to discuss each answer with the class. An example of one of the answers could be: three one dollar bills, five quarters, and three pennies. If the teacher finds this value too hard to begin with, they can lessen it to just coin values. Each class works at a different pace and it is up to the teacher's discretion.
I give students about ten additional minutes to discover this process on their own. As students are working, I circle the room to reinforce reading and writing numbers.
Can you write the amount?
How do you know it is written correctly?
What is the value of each digit?
How Much Change Do I Get?
Materials: Independent task two.docx
In this portion of the lesson I want to create a real world experience to foster students learning. To do this I ask students to move into their assigned groups! Then, I tell students by fourth grade, you all should be able to recognize all the coin amounts and write their correct values, as well as the dollar amounts. Forming different values by combining the dollars and coins should also be achieved, as well as addition and subtraction of monetary values. Learning to line up the decimal points and carrying them throughout a problem can be a challenging concept but must be learned before approaching multiplication and division of money, which usually begins in fifth grade.
To do this guys we are going to set up four small stores within your groups. Each of you will be given a set amount of money to purchase items. Be sure to pay attention to the key factors listed above. The students seem to very excited about the activity. Many of them are already pointing to the things they want to buy.
to make sure students have a good idea of what they will be doing, I start review coin values: for example $.25 + $.10 = $.35. Next will still use the coin values but will mix the coins together to make new values like $.93 + $.57 = $1.50. I repeat this a couple of times just to make sure students understand how to align the decimals correctly. I ask student to tell me the value of each digit. How do you know? I reinforce carrying skills also. Because this concept is a two step process, I ask can anyone tell me how much change I will get if I gave the cashier $10.00. $8.50 Great job guys! Before we start we need to determine who will be the cashier for each group. To do this I ask students to write their name on a small piece of paper and place it in to a bowl one group at a time. The person's name pulled from the bowl will be the cashier. Students tend to argue over any little thing, so deciding what role they all will play during this hands-on activity will help minimize frequent interruptions.
As students are working, I circle the room to check for understanding.
1. How many items can you buy?
2. How do you know?
3. How much will it cost?
4. How much money do you have?
5. How much do you have left?
6. What is the value of the digit? ( ask for value of each digit)
After students are finished working, I ask a 2 groups to share what their learning experience. I reflect on my students response to ensure they understand the process adding and subtracting money.
Materials: Independent task two.docx
In this portion of the lesson I ask students to move back to their assigned seats. I tell them they are ready to get their count on! Who is ready? Student yell out, "We are!" I give them their assignment, and move into facilitator mode. As students are working, I circle the room to check for understanding. I take note of how well students are responding to the how and why questions. I use their responses to decide if they need additional time on this particular objective.
What do you start counting with?
How many times do you count by twenty five?
How many times do you count by tens, fives and ones?
On which side of the decimal do you write the cents on?
How much much do you have?
How much will you have left? How do you know?