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Modeling and Solving Problems Involving Fractions

Unit Plan

Modeling and Solving Problems Involving Fractions

Objectives

Objectives haven't been entered into the unit plan.

Essential Questions

How are relationships represented mathematically?
How can mathematics support effective communication?
How is mathematics used to quantify, compare, represent, and model numbers?
What does it mean to estimate or analyze numerical quantities?
What makes a tool and/or strategy appropriate for a given task?

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Formative Assessment

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    Multiple-Choice Items:

    1. How many total pieces would be created in a paper-folding activity used to model ?

    A  7

    B  12

    C  42

    D  48

     

     

    1. Which expression would be a multiplication sentence used to represent the following area model?

        

     

     

     

     

    1. What answer is represented by the following area model?

     

    1. Simplify the following expression: .

    1. Which of the following equations will give you the quotient ?

    1. Gretchen walked 6 miles one day at the park. Gretchen rested every  of a mile. How many times did she rest during her 6-mile walk?

    A  8 times

    B  9 times

    C  4 times

    D  6 times

     

    If it would be helpful, draw a pictorial representation to help solve problems 7, 8, and 9.

    1. An oil mechanic can change the oil in a car in  of an hour. If he works a  hour shift, for how many cars can he change the oil?

    A  7 cars

    B  11 cars

    C  20 cars

    D  22 cars

     

    1. You decide to make bookmarks out of a wide leather material to give to some of your friends. You have 38 inches of the leather material. Each bookmark will be  inches long. How many bookmarks can you make from this material?

     

    A  5 bookmarks

    B  7 bookmarks

    C  8 bookmarks

      D  9 bookmarks

     

    1. Jake went jogging. He ran four miles and noticed he ran for  of an hour. How many miles can he jog per hour if he keeps his current pace?

     

    Multiple-Choice Answer Key:

    1. C
    2. A
    3. B
    4. B
    5. C
    6. B
    7. D
    8. C
    9. A

     

     

    Short-Answer Items:

    1. A box of 24 cupcakes is arranged so that there are 4 rows of 6 cupcakes each. Three-fourths of the cupcakes are vanilla, and  of the vanilla cupcakes have chocolate frosting. Create a visual representation of an area model using a table array or paper folding to show what fraction of the total number of cupcakes is vanilla with chocolate frosting. Explain your model.

     

    1. Draw a model of the expression  and simplify it or solve through repeated subtraction.

     

    1. Create a division word problem using the following numbers:  and . Solve the problem using a picture representation.


    Short-Answer Key and Scoring Rubric:

    1. A box of 24 cupcakes is arranged so that there are 4 rows of 6 cupcakes each. Three-fourths of the cupcakes are vanilla, and  of the vanilla cupcakes have chocolate frosting. Create a visual representation of an area model using a table array or paper folding to show what fraction of the total number of cupcakes is vanilla with chocolate frosting. Explain your model.

     

                                                                                                       

     

     

    1. Draw a model of the expression  and simplify it or solve through repeated subtraction.

    Possible explanation:

    See following rubric.

    1. Create a division word problem using the following numbers:  and . Solve the problem using a picture representation.

    Possible explanation: Brenda had  cups of brown sugar. The recipe for the batch of cookies she was making needed  of a cup. How many batches of cookies could she make with this amount of brown sugar?

    Answer: 3 for any problem set up as or  for any situation with

    See following rubric.

     

    Use this scoring rubric for questions 10–12.

     

    Points

    Description

    2

    • Written explanation is thorough, clear and supported with visual representation.
    • Complete understanding of multiplication, division, and modeling with fractions is demonstrated
    • Answer is correct.
    • Requirements of the problem are met.

    1

    • Written explanation is brief and is partially supported by the visual representation.
    • Partial understanding of multiplication, division, and modeling with fractions is demonstrated.
    • Answer is incorrect due to a minor mathematical error.
    • Requirements of the problem are partially met.

    0

    • Written explanation is brief or missing, and there is no visual representation.
    • No understanding of multiplication, division, and modeling with fractions demonstrated.
    • Answer is incorrect due to a major mathematical error/misunderstanding or is missing.
    • Requirements of the problem are not met.

     

     

    Performance Assessment:

     

    Part I

     

    A baker is making doughnuts. He has  cups of batter left. Each doughnut requires  cup of batter. Write an expression that shows how many doughnuts can be made with the remaining batter.

     

    ________________________________________________________________________

     

    A baker had some boxes of doughnuts. He took  of the boxes for samples. He put  of the doughnuts from each box on a sample tray. Write an expression that shows the fraction of the doughnuts the baker put on the sample tray.

     

    ________________________________________________________________________

     

    A teacher bought some doughnuts and of them had chocolate frosting. Only  of the doughnuts had cream filling. Write an expression to show the fraction of chocolate doughnuts with cream filling the teacher bought.

    ________________________________________________________________________

     

    Using one of the expressions, create a picture representation and solve.

     

     

     

     

     

     

     

     

    How is using a picture representation helpful in solving word problems?

     

     

    Part II

     

    To keep the doughnuts fresh in the boxes and to stop the doughnuts from sticking to the insides of the boxes, the bakery owner decided to line the insides of the boxes. Each box that fits 6 doughnuts requires  inches of liner. One roll of liner is 21 feet long. How many boxes can be lined from one roll?

     

     

    Identify the important information you need to solve this problem.

     

    ______________________________________________________________________________

     

     

    How do you know what operation to use to solve this problem?

     

    ______________________________________________________________________________

     

     

    Solve the this problem using any method you choose. Be sure to include all the necessary steps.

     

     

     

     

     

     

     

     

     

    Part III

     

    The owner of the bakery across the street wanted to know the fraction of various kinds of doughnuts left over after a day’s business. At the end of the day,  of the doughnuts had chocolate frosting. If  of the doughnuts with chocolate frosting also had rainbow sprinkles, what fraction of the leftover doughnuts had both chocolate frosting and rainbow sprinkles? Use the area model to solve.

     

    Performance Assessment Key:

     

    Part I: Solution

     

    A baker is making doughnuts. He has  cups of batter left. Each doughnut requires  cup of batter. Write an expression that shows the number of doughnuts that can be made with the remaining batter. 

     



    A baker had some boxes of doughnuts. He took  of the boxes for samples. He put of the doughnuts from each box on a sample tray. Write an expression that shows the fraction of the doughnuts the baker put on the sample tray.

     

     

    A teacher bought some doughnuts and of them had chocolate frosting. Only  of the doughnuts had cream filling. Write an expression to show the fraction of chocolate doughnuts with cream filling the teacher bought.

     

     

    Using one of the expressions, create a pictorial representation and solve.

     

    There are 12 s in . The answer: The baker can make 12 doughnuts.

     

    How is using a picture representation helpful in solving word problems?

     

    When you use a pictorial representation, you can visualize what happens when dividing fractions. You can “see” what the answer is when you are done without necessarily using an algorithm. Unfortunately, it might not always be practical or easy to represent a problem pictorially.

     

    Part II: Solution

     

    To keep the doughnuts fresh in the boxes and to stop the doughnuts from sticking to the insides of the boxes, the bakery owner decided to line the insides of the boxes. Each box that fits 6 doughnuts requires  inches of liner. One roll of liner is 21 feet long. How many boxes can be lined from one roll?

     

    Identify the important information you need to solve this problem.

     

     inches for each box. Roll has 21 feet. Need to make feet into inches. 12 × 21 = 252 inches.

     

    How do you know what operation to use to solve this problem?

     

    I need to divide because I have been given a total amount (21 feet). I need to break up that amount into -inch pieces.

     

    Solve this problem using any method you choose. Be sure to include all the necessary steps.

    Part III: Solution

     

    The owner of the bakery across the street wanted to know the fraction of various kinds of doughnuts left over after a day’s business. At the end of the day,  of the doughnuts had chocolate frosting. If  of the doughnuts with chocolate frosting also had rainbow sprinkles. What fraction of the leftover doughnuts had both chocolate frosting and rainbow sprinkles? Use the area model to solve.

    Answer:

     (or ) of the doughnuts have both chocolate frosting and rainbow sprinkles.

     

    Performance Assessment Scoring Rubric:

    Points

    Description

    4

    • Mathematics is correct with complete work shown.
    • Written explanations are thorough, detailed, and clear.
    • Advanced understanding of multiplication, division, and modeling with fractions is displayed.
    • Answer exceeds problem requirements and possibly incorporates multiple methods/solutions.
    • Pictorial representation is appropriate, excellent quality, and creative.

    3

    • Mathematics is correct with work shown.
    • Written explanations are thorough and clear.
    • Good understanding of multiplication, division, and modeling with fractions is displayed.
    • All problem requirements are met.
    • Pictorial representation is appropriate, good quality, and neat.

    2

    • Mathematics is correct with minimal or no work shown.
    • Written explanations are present but lacking some detail.
    • Partial understanding of multiplication, division, and modeling with fractions is displayed.
    • Most problem requirements met.
    • Pictorial representation is complete but may have errors.

    1

    • Mathematics is incorrect with some work shown.
    • Written explanations are incomplete and lack detail.
    • Little understanding of multiplication, division, and modeling with fractions is displayed.
    • Does not meet a majority of the problem.
    • Pictorial representation is incomplete, inappropriate for the situation, or missing.

    0

    • Mathematics is incorrect with no work shown.
    • Written explanations are illogical or not present.
    • No understanding of multiplication, division, and modeling with fractions is displayed.
    • Does not meet the problem requirements.
    • Pictorial representation is missing.

     

Final 04/12/13
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