Tuesday, August 4, 2015

Lesson Plan: Adding & Subtracting Decimals

This lesson utilizes enVision Math, but ideas can be adapted for other texts.  Many of the hyperlinks will direct you to a place to download the resources used throughout this lesson. (Note: You must have ActivInspire downloaded to view the Promethean Board slides)

Subject: Math
Grade: 5th

Source: enVision Math 2.6 & 2.7 (2 day lesson)

Integration of Learning Outcomes:

· Students will be able to compute sums of decimals involving tenths, hundredths, and thousandths by making sense of problems and persevering in solving them, reasoning abstractly and quantitatively, constructing viable arguments and critiquing other’s reasoning, looking for and making use of structure, and looking for and expressing regularity in repeated reasoning. (enVision)

· Students will be able to compute differences of decimals involving tenths, hundredths, and thousandths by reasoning abstractly and quantitatively, constructing viable arguments and critiquing the reasoning of others, attending to precision, and looking for and making use of structure. (enVision)

Standards

· 5.NBT.7: Add and subtract decimals to hundredths, using strategies based on properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used.

· 5.NBT: Add and subtract decimals to hundredths using concrete models or drawings.

· M05.A-T.2.1: Use whole numbers and decimals to compute accurately (straight computation or word problem).



Anticipatory Set

· What are some situations where you would have to add/subtract decimals? (Example: money)

Day 1 PBIL (Addition): Shoprite received two large boxes of Halloween candy to sell. The first box weighs 11.39 pounds. The second box weighs 14.27 pounds.  How many boxes of candy does Shoprite have in all?  Use any method to decide.

· Students will solve individually on their whiteboards, and then compare their answers to their small groups.

· Go over answers as a class.

Day 2 PBIL (Subtraction): Ms. Garcia has a length of wire that is 32.7 m long.  She has another length of wire that is 15.33 m long. How much longer is the one wire than the other? Use any method to decide.

· Students will solve individually on their whiteboards, and then compare their answers to their small groups.

· Go over answers as a class.

Procedures

Day 1: Addition

Play Study Jams: Addition of Decimals.  Go through all the steps.  Have students follow the steps by solving the problem on their whiteboard.
·      Step 1: Annotate the problem and break it down, pulling out the important information.
·      Step 2: Solve the problem on whiteboards before revealing the process and answer.
·      Answer: How much change does Zoe have left?

Use "checkbooks" to practice adding and subtracting decimals
Complete the first problem of the Study Jams “Try It!”  Students will solve the problem on their whiteboards.  They will compare their answers to a partner’s.  Have a student write the problem and answer on the whiteboard.  Then, go over the answer.

Explain that adding decimals is very common in the real world.  Explain that adults add decimals in money form to help balance their checkbooks.  Explain that students will simulate using checkbooks.  Pass out the pre-made “checkbooks.”  Explain that people use checkbooks to keep track of how much money is in their banking account.  Explain the different parts of the checkbook.

Start by giving each student a balance of $100.00.  Model how to fill out the checkbook on the document camera.  Next, state that students made $46.13 by helping their parents or guardians and they will be putting that money into their bank account.  Line up the numbers, and modeling adding $100.00 + $46.13 = $146.13 in their checkbooks.  Students should follow along and copy into their checkbooks. 

Set up the next problem: It was the student’s birthday.  From all the cards and presents, they received a total of $75.58 and want to put that money into their bank account.  Model how to setup the problem in the checkbook.  Have students solve the problem individually in their checkbook.  Students may use their whiteboards to solve the problem first if they need more room.  Go over the answer as a class ($221.71).

Now, each group will receive a stack of cards with a price value and reason for adding money.  They will put the cards face down.  They will pick up one card at a time and work as a group to fill out their checkbook.  Do a model as a class, and have everybody follow along and copy the example into their checkbook.  Students will work as a group through their small stack of cards.

· Example: Card reads “Paycheck from work, +$210.15. Add $221.71 + $210.15 = $431.86

Students will complete pg. 46-47, #14, 15, 16, and 19 from the independent practice of their textbooks.  Do #14 as a class on the whiteboard.  Show that the decimals need to be lined up and that zero may need to be added as a placeholder if there appears to be a place that is missing.

Once students have completed the independent practice and have it checked by a teacher, students will have a choice of two stations:

·      Grocery Shopping: Students will complete the “Grocery Shopping List” worksheet.  Each pair will receive a grocery ad.  Students will complete the exact cost column first before practicing estimating.

·      Dinner Menu: Students will receive a menu with a worksheet attached.  Students will choose their meals and record the information on the worksheet.

If students finish both of the stations, they may finish the independent practice from their textbook.

Day 2: Subtraction

Complete the Study Jams: Subtraction of Decimals.  Go through all the steps.  Have students follow the steps by solving the problem on their whiteboard.
·      Watch Out: Annotate the problem and break it down, pulling out the important information.
·      Step 1: Have students line up the problem on their whiteboard and solve the problem.
·      Go through the steps until the problem is solved.

Complete the second problem of the Study Jams “Try It!”  Students will solve the problem on their whiteboard.  They will compare their answers to a partner’s.  Have a student write the problem and answer on the whiteboard.  Then, go over the answer.

Explain that subtracting decimals is very common in the real world.  Explain that adults subtract decimals in money form to help balance their checkbooks.  Ask students, “What are some reasons that we may need to subtract money from our checkbooks?”  Students will talk in a group before having 2-3 students share their answers.  Explain that students will simulate using checkbooks with subtraction.

Ask students what their remaining balance was from the addition problems in the previous day’s lesson.  Model how to fill out the checkbook on the document camera with subtraction.  Mention that students have to pay a bill of $66.89.  Model how to subtract in the checkbook, and have students follow along and copy into their checkbook.

Set up the next problem: It was a friend’s birthday and they decide to buy them a gift that costs a total of $93.12.  Have students solve the problem individually in their checkbook. Students may use their whiteboards to solve the problem first if they need more room.  Go over the answer as a class.

Now, each group will receive a stack of cards with a negative price value and reason for spending money.  They will put the cards face down.  They will pick up one card at a time and work as a group to fill out their checkbook.  Students will work as a group through their small stack of cards.

Do #2 and #16 from pg. 48-49 in the textbook as a class.  Mention lining up decimals and adding zeros as a placeholder.  Have students solve the problems on their whiteboards.

Seasonal: Students will complete the Halloween Math riddle worksheetthat requires using addition and subtraction of decimals.  After finishing the Halloween Math riddle, they will do the decimal addition and subtraction task card activity with a worksheet.

Students will finish the independent practice if time remains and they have completed all the activities.

Differentiation

· Students will work with a partner or small group, allowing them to teach each other or build ideas off each other.

· Centers and hands-on activities provide different ways for students to learn. Various centers and activities will benefit visual and kinesthetic learners.

· Students are allowed to solve the PBIL in any method that they prefer. If students are more comfortable with estimating, they may do so. If they are comfortable with drawing pictures, they may do so.

· Activities were made to be engaging to keep student interest. They also relate to real-world activities to keep them motivated and realize that they will need various tasks in the real world.

Closure

· State that students have learned how to add and subtract with decimals.

· Write an addition problem on the board and a subtraction problem on the board and have students solve the problems. Collect as an exit slip.

Formative/Summative Assessment

· Walk around, observe, and assist while students are completing word independently or in groups.

· Collect exit slip to see how well students are doing with adding and subtracting decimals.

· Collect worksheets from centers to assess how well students understand the processes of adding and subtracting decimals.

· Students will be tested on the material learned in this lesson at the end of a unit through a summative unit test.

Materials

·      Pre-made checkbooks made with construction paper, paper checks worksheet, and check register worksheet
·      Addition and subtraction statement and price cards
·      Addition and subtraction task cards and worksheet
·      Grocery ads
·      Menu Worksheet
·     Menu
·      Document camera
·      Whiteboard and markers
·      Promethean Board with Internet access & slides

Technology

·      Promethean Board with Internet access & slides
·      Document camera

Reflection on Planning

I remembered learning how to balance a checkbook when I was in elementary school.  I thought that this would be a perfect opportunity to learn the basics of keeping a checkbook since the lessons required students to add and subtract decimals.  Using a checkbook is all addition and subtraction of decimals.  It gives the students a real-world example and shows that they will need to know addition and subtraction of decimals in everyday life.  It gives the lesson a purpose, and makes it more meaningful.

I also wanted to add different centers that would be interactive.  I found a few different activities that also connected to the real world, being the grocery shopping list and ordering off a menu.  Again, it showed the everyday usage of adding and subtracting decimals, thus giving the assignment a purpose.  I also found a Halloween worksheet that related to the timely season and involved the addition of decimals.

Reflection of Instruction

I originally had this lesson separated into two different days.  However, an unexpected meeting made us miss a whole period of math.  During this meeting, students completed centers that they had started before but hadn’t finished so they would be able to review and practice math.  Therefore, I had to squeeze both addition and subtraction into one class period.  First, we did the addition with the PBIL and Study Jams.  Students seemed to grasp the concept quickly.  We skipped over the addition centers.  Then, we did the subtraction PBIL and Study Jams.  Again, students grasped the content quickly.  I tried to express the importance of lining up the decimal when adding and subtracting.

Last, I showed students how to do checkbooks.  They were really excited about using the checkbooks.  I thought that they would like it, but they were much more into it than I even thought originally.  I showed them what the information meant and where to write the information.  There was a little confusion about what deposit and withdrawal meant.  Then, I had them write a plus sign or minus sign above either payment or withdrawal so that students would know which column was which.  We did a few examples together as a class.  We ran out of time so we couldn’t do the checkbook group activity or any of the centers.  We may do centers during the review day.

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