ADDING FRACTIONS Name: Ryan Moyer Grade Level: 7 Materials Required: Fraction bars (enough for pairs to share) PowerPoint SMARTboard Homework sheets Time Allotted: 20 minutes Subject(s): Math Michigan Content Expectations: CCSS.Math.Content.7.NS.A.1 Apply and extend previous understandings of addition and subtraction to add and subtract rational numbers; represent addition and subtraction on a horizontal or vertical number line diagram. Objective: The student will individually apply previous understandings of addition to add rational numbers by correctly answering at least 7 of 10 problems on the handout to demonstrate proficiency. Assessment: Formative: Students will take a brief pre-test before the lesson begins to test their prior knowledge to addition of fractions. (Formal) Students will solve addition problems throughout the lesson and do a thumbs up when they have the answer. (Informal) Summative: Students will have a worksheet to fill out at the end of the lesson. (Formal: assessed based on rubric) Instructional Procedure: What information do students need to accomplish the objective? 1. Anticipatory Set: (Allotted Time: 5 minutes) a. Start the PowerPoint. b. Ask students to add the apples and oranges. c. Tell them that we can only add things that are alike. d. Students do the pre-test on the PowerPoint. e. Give students 2 minutes to complete 2 problems and then collect the pre-tests. f. While students are doing their pre-test, pass out fraction bars. 1
2. State Purpose and Objective of Lesson: (Allotted Time: 1 minute) a. As you can probably tell, our objective today is to learn how to add fractions. b. You ll need to know this kind of math in multiple areas of life taking measurements, following recipes when cooking. c. We ve learned how to find common multiples and that will help us today when we learn to add fractions. 3. Instruction: (Allotted Time: 13 minutes) a. Direct Interactive Instruction/Modeling: i. What I m doing on the board, I want you to do with your fraction bars in front of you. ii. Take the one whole bar and all five 1/5 bars and line them up. iii. This is like separating the one into 5 smaller parts, which makes each part worth 1/5 because it makes 5 parts out of one whole. iv. Make a box around the first two one-fifths boxes. Each of these boxes is worth 1/5. If I add these two together what do you think I get? 1 5 + 1 5 = 2 5. v. Box the next one-fifth box. If I take those 2 fifths and add another fifth, what do I get? 3 5 vi. Ask students what 2 5 + 2 5 is. vii. Then ask about 2 5 + 3 5. This is 5 5. viii. When we did this, we added the tops together and kept the bottoms the same. ix. Let s try another problem. What do you think we might get if we added ⅓ and ½? Take a guess. How did you get that? x. Remember that we can only add like things so we have to make our denominators the same. xi. Do you remember what the word multiple means? (A number that you get when you multiply a number by another number) xii. If the bottoms need to be the same, what do you think we can do to change them? (We can find a common multiple of the denominators to replace the 2 and 3) xiii. What are some multiples of 3? (Write them on the board.) What are some multiples of 2? Do they have anything in common? (6, 12, etc.) We can use any common multiple, but it s easiest to use the smallest. We call this the least common multiple and when it s the denominator, we call it the Least Common Denominator (or LCD). xiv. Have students line up their ⅓ and ½ fraction bars and then use their sixths fraction bars to find the answer: 5 6. xv. Explain the creative use of one. Remember when we found that 5 = 1. We 5 can use that idea to make our fractions the same. If we want to make ⅓ have a denominator of 6, what do we do to make that 3 change to 6? 2
Multiply by 2. We can t just multiply by 2. Remember that one times anything is itself. We can multiply by 2 to get 6 in the denominator. What 2 would we multiply by to get ½ to have a 6 in the denominator? (3 over 3) b. Guided Practice: i. I m going to put up an example on the board. 1 8 + 3 4 ii. With a partner, I want you to solve this problem. Together, find a common multiple. One of you will solve the problem using your fraction bars and the other person will write the problem using numbers and the creative use of one. iii. When most students are done, ask students what they got and confirm that answer with other pairs in the class. iv. Let s try one more. I want you to switch roles with your partner. 2 9 + 1 3 c. Independent Practice: i. Now students will get their homework assignment. ii. If time allows, they can begin the homework in class. 4. Differentiated Consideration (Adjust instruction and assessments, tools, resources or activities for students who): Finish quickly: Have options of other activities for the students to do or have them help students who are struggling. Struggle to complete activity/assessments: Have students who finish quickly help the students who struggle. 5. Closure: (Allotted Time: 1 minute) a. Today our objective was to be able to add fractions. What is the main thing that we have to keep in mind when we add fractions? b. We can only add like things! 6. References: Fraction strips to twelfths labeled. Retrieved from http://lrt.ednet.ns.ca/pd/blm/pdf_files/ fraction_strips/fs_to_twelfths_labelled.pdf Fractions worksheet. Retrieved from http://www.math-aids.com/fractions/ Adding_Fractions.html. Rainbow Fraction bars. Retrieved from http://exchange.smarttech.com/ details.html?id=aa6cf2a8-fc09-4064-a900-4f87f3f2af87. 3
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Fraction Bars Why I chose this strategy: This strategy allows students to have a visual in front of them while they learn about adding fractions. Fractions can be tricky to understand so having the visuals can give a concrete representation. Benefits of this strategy: Students have a visualize the abstract concept of fractions. Students can put the abstract concept of fractions Possible cons of this strategy: Since the fraction bars are cut out paper, they can be imprecise. Purchased fraction bars would be more accurate. For fractions that have different denominators, we would have to use common denominators. Fractions that add to more than one could be problematic because we only have enough of each denominator to get 1 whole. 6