I begin this warm up with counting exercises. I review counting by 5s and 10s as this skill is crucial to counting dimes and nickels. Identifying money amounts is an important skill for second graders who are expected to be able to solve coin word problems by the end of the year (2MD.C.8). I write 20, __, 30, ___, ____, ____, 50 on the board and ask students to copy this into their math journals and fill in the blanks. I give students time to write the problem in their journals and I circulate around to see which students are having trouble with this. I keep a clipboard where I can jot down names and areas of difficulty.
I ask one student to come up and fill in the missing numbers on the board. He/she would fill in 20, 25,30, 35,40, 45,50. I ask students to help me check this by reading the numbers aloud as a class. I put several similar problems counting by 5s and 10s. I write 50, ____, 70, ____, 90, _____; I also write 65, _____, 75,_____, 85, _____, 95, 100.
In this warm up session I also want to review the looks of the coins. I have a set of oversized cardboard coins that can be seen by all students in the room. I hold up the penny and ask what it is. Everyone appears to be able to recognize the penny and know that it is one cent. Next I hold up the quarter. I remind students that it is the biggest of the coins we usually see, and also worth the most. Many of the students recognize the quarter and that it is 25 cents. Next I hold up the dime. I tell students that it is the littlest coin but it is not worth the least. This hint helps several students identify the dime and know that it is 10 cents. Finally I hold up the nickel and students identify it. I tell students that today we will be working with coins.
At this point in the year many students still struggle with recognizing which coin is which. They know the dime is the smallest coin, but often think it must then be worth 5 cents. The nickel and the quarter look a lot alike and are hard for students to see the differences. I give each child a set of 1 of each coin. I ask them to look at the coins, turn them over, look for words or hints about the value of the coin. I tell students they can even set them on a page in their math journals and trace them and write down what they are worth.
My goal is to introduce coins and eventually to have students figure out how much money a small collection of coins would be worth. I want students to be able to solve simple word problems involving coins (2MD.C.8) such as if I have 3 pennies and 1 nickel, what is that worth? If I have 1 dime and 1 penny, how much money do I have?
Today I am going to add a game that will get students up and moving and also give them a chance to identify the coins and their values.
I form the class into 2 lines facing each other. I give one line pieces of paper marked 1cent, 5 cents, 10 cents, 25 cents. The other line is given the cardboard coins for the same amounts. I explain to students that when I tell them, they will move about and find a partner who has the coin or amount that matches theirs. They will form the 2 lines with partners across from one another.
I give the signal to start and students move about holding up their coin or amount, calling out what they have and eventually forming 2 lines with matching amounts facing each other. The students hold up their coins and amounts to show the pairs.
I collect the coins and amounts, shuffle them and hand them out again. The students repeat the matching process.
I did have several students worried because they ended up with the same partners. I told them that was fine as long as their amounts matched.
At the end of the game I called the partners by coin to hand in their materials and return to their seats.
Students need time to practice with coins. I break students into 2 small groups for coin practice. I have each group work for 15 minutes and then the groups switch.
One group works on a math practice page identifying coin amounts. I allow them to have the actual coins and values from the warm up on their desks to help them. I generated an easy coin value page from www.mathfactcafe.com. You can tailor the page to meet the needs of your students. The page gives a variety of problems in finding the value of a small number of coins. I collect this page at the end of the 15 minutes to assess student understanding.
The other group shops for small toys that have price tags of 5 cents, 10 cents, 15 cents, 20 cents, 25 cents, and other amounts from 5 to 14 cents. Students take turns choosing an item and counting out the coins while a second child acts as the storekeeper and counts out the payment to make sure their partner paid the right amount.
I sit with the shopping group to help them find the coins, and to informally assess who can count coins and who may not know all the coins and may need extra practice in the future.
With these two formative assessments, I get different information about student understanding. When students have the actual coins they are modeling with mathematics to get the right amount of money to buy the toy (MP4). They are manipulating the coins and counting to get a total. WIth the worksheet students need to make sense of the problems presented, and then use their reference material (coins and amounts) to persevere in solving the problems. (MP1)
After each group has had practice time, students clean up and come to the circle. I close with a problem that I write on the easel. " If you want to buy a balloon for 12 cents and you only have 2 dimes, what could you do?" I ask children to think about the problem and then offer suggestions. We record some of the suggestions and then evaluate which ones might make sense.
Bringing students back to considering their own thinking and critiquing other’s solutions is a critical component of my daily math lesson because it meets the mathematical process standard MP3. Students are beginning to look at their own thinking and the thinking of others and evaluating if it is logical.