Operations With Fractions MODULE 4 - School Webmasters

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Operations withFractions?4MODULELESSON 4.1ESSENTIAL QUESTIONApplying GCF andLCM to FractionOperationsHow can you use operationswith fractions to solvereal-world problems?COMMONCORE6.NS.4LESSON 4.2Dividing FractionsCOMMONCORE6.NS.1LESSON 4.3Dividing MixedNumbersCOMMONCORE6.NS.1LESSON 4.4 Houghton Mifflin Harcourt Publishing Company Image Credits: (c)Tetra Images /AlamySolving MultistepProblems withFractions and MixedNumbersCOMMONCORE6.NS.1Real-World Videomy.hrw.commy.hrw.comTo find your average rate of speed, divide the distanceyou traveled by the time you traveled. If you ride in ataxi and drive 12 mile in 14 hour, your rate was 2 mi/hwhich may mean you were in heavy traffic.my.hrw.comMath On the SpotAnimated MathPersonal Math TrainerGo digital with yourwrite-in studentedition, accessible onany device.Scan with your smartphone to jump directlyto the online edition,video tutor, and more.Interactively explorekey concepts to seehow math works.Get immediatefeedback and help asyou work throughpractice sets.75

Are YOU Ready?PersonalMath TrainerComplete these exercises to review skills you will needfor this module.Write an Improper Fractionas a Mixed NumberEXAMPLE13 55 55 355 1 1 35 2 35 2 35my.hrw.comOnlineAssessment andInterventionWrite as a sum using names for one plus aproper fraction.Write each name for one as one.Add the ones.Write the mixed number.Write each improper fraction as a mixed number.1. 942. 83233.6114.2175.5156.8337.10298.12Multiplication FactsEXAMPLE7 6 7 6 42Use a related fact you know.6 6 36Think: 7 6 (6 6) 6 36 6 429. 6 510. 8 911. 10 1112. 7 813. 9 714. 8 615. 9 1116. 11 12Division FactsEXAMPLE63 7 Think:63 7 9So, 63 7 9.7 times what number equals 63?7 9 63Divide.76Unit 217. 35 718. 56 819. 28 720. 48 821. 36 422. 45 923. 72 824. 40 5 Houghton Mifflin Harcourt Publishing CompanyMultiply.

Reading Start-UpVisualize VocabularyUse the words to complete the triangle. Write the review wordthat fits the description in each section of the triangle.partof a wholetop numberof a fractionVocabularyReview Wordsarea (área) denominator(denominador) fraction (fracción)greatest common factor(GCF) (máximo comúndivisor (MCD))least common multiple(LCM) (mínimo comúnmúltiplo (m.c.m.))length (longitud) numerator (numerador)product (producto)width (ancho)Preview Wordsbottom number of a fractionmixed number (númeromixto)order of operations (ordende las operaciones)reciprocals (recíprocos)Understand Vocabulary Houghton Mifflin Harcourt Publishing CompanyIn each grouping, select the choice that is described by the givenvocabulary word.1. reciprocalsA 1:1531B 4 6C3and 5352. mixed number1 1A -3 51B 32C -53. order of operationsA 5-3 2 0B 5-3 2 4C 5-3 2 6Active ReadingLayered Book Before beginning the module,create a layered book to help you learn theconcepts in this module. Label each flap withlesson titles. As you study each lesson, writeimportant ideas, such as vocabulary andprocesses, under the appropriate flap. Referto your finished layered book as you work onexercises from this module.Module 477

MODULE 4Unpacking the StandardsUnderstanding the standards and the vocabulary terms in thestandards will help you know exactly what you are expected tolearn in this module.COMMONCORE6.NS.1Interpret and computequotients of fractions, andsolve word problems involvingdivision of fractions byfractions, e.g., by using visualfraction models and equationsto represent the problem.Key VocabularyWhat It Means to YouYou will learn how to divide two fractions. You will also understandthe relationship between multiplication and division.UNPACKING EXAMPLE 6.NS.1Zachary is making vegetable soup. The recipe makes 6 34 cups ofsoup. How many 1 12 -cup servings will the recipe make?6 34 1 12quotient (cociente)The result when one number isdivided by another.27 324fraction (fracción)A number in the form ba , whereb 0. 9227 234 4 21The recipe will make 4 12 servings.6.NS.4Find the greatest commonfactor of two whole numbersless than or equal to 100 andthe least common multiple oftwo whole numbers less than orequal to 12. Use the distributiveproperty to express a sum oftwo whole numbers 1–100 witha common factor as a multipleof a sum of two whole numberswith no common factor.Visit my.hrw.comto see all theCommon CoreStandardsunpacked.my.hrw.com78Unit 2What It Means to YouYou can use greatest common factors and least common multiplesto simplify answers when you calculate with fractions.UNPACKING EXAMPLE 6.NS.4Add. Write the answer in simplest form.1Use the LCM of 3 and 6 as 16 26 163a common denominator.2 1 6Add the numerators. 363 3 6 3Simplify by dividing by the GCF.The GCF of 3 and 6 is 3. 12Write the answer in simplest form. Houghton Mifflin Harcourt Publishing CompanyCOMMONCORE

LESSON4.1?Applying GCF andLCM to FractionOperationsESSENTIAL QUESTIONCOMMONCORE6.NS.4Find the greatest commonfactor and the leastcommon multiple of twowhole numbers How do you use the GCF and LCM when adding, subtracting,and multiplying fractions?EXPLORE ACTIVITYCOMMONCORE6.NS.4Multiplying FractionsTo multiply two fractions you first multiply the numerators and then multiplythe denominators.Math On the Spotmy.hrw.comnumerator numeratornumerator denominator denominatordenominatorThe resulting product needs to be written in simplest form. Below are twomethods for making sure that the product of two fractions is in simplest form.EXAMPLE 1Multiply. Write the product in simplest form.A 13 35Write the problem as a single fraction.Multiply numerators. Multiply denominators. Houghton Mifflin Harcourt Publishing CompanySimplify by dividing by the GCF.The GCF of 3 and 15 is.Write the answer in simplest form.B 67 23Write the problem as a single fraction.The 6 in the numerator and the 3 in thedenominator have a GCF of. Divide6 and 3 by 3 and write the quotients in the boxes.Use the quotients from the previous steps tomultiply the numerators and denominators.1 31 35 33 53 15 6 23 76 27 3 2 7 Lesson 4.179

EXPLORE ACTIVITY (cont’d)YOUR TURNMultiply. Write each product in simplest form.PersonalMath TrainerOnline Assessmentand Interventionmy.hrw.com1. 16 352. 34 793. 37 234. 45 2787 5.10216. 67 16Multiplying Fractions andWhole NumbersMath On the Spotmy.hrw.comTo multiply a fraction by a whole number, you rewrite the whole number as afraction and multiply the two fractions. Remember to use the GCF to write theproduct in simplest form.EXAMPLE 2COMMONCORE6.NS.4A class has 18 students. The teacher asks how many students in the class havepets and finds 59 of the students have pets. How many students have pets?Estimate the product. Multiply the whole number by the nearestbenchmark fraction.5is close to 12 , so multiply 12 times 18.91 18 92STEP 2Multiply. Write the productin simplest form.5 189Math TalkMathematical PracticesHow can you checkto see if the answer iscorrect?518 18 59 192Unit 25 1895· 1895(18)9Rewrite 18 as a fraction. 18 59 1Simplify before multiplying using the GCF.5 2 1 1Multiply numerators. Multiply denominators.10 10 1Simplify by writing as a whole number.110 students have pets.805times 18You can write9three ways. Houghton Mifflin Harcourt Publishing Company Image Credits: Life onwhite/AlamySTEP 1

Reflect7.Analyze Relationships Is the product of a fraction less than 1 and awhole number greater than or less than the whole number? Explain.YOUR TURNMultiply. Write each product in simplest form.8.5 2489.3 20510.1 8311.1 14412.7 731013.3 10210PersonalMath TrainerOnline Assessmentand Interventionmy.hrw.comAdding and Subtracting FractionsYou have learned that to add or subtract two fractions, you can rewrite thefractions so they have the same denominator. You can use the least commonmultiple of the denominators of the fractions to rewrite the fractions.EXAMPL 3EXAMPLECOMMONCORE6.NS.4 Houghton Mifflin Harcourt Publishing Company81Add15 6 . Write the sum in simplest form.STEP 1my.hrw.comMy NotesRewrite the fractions as equivalent fractions. Use theLCM of the denominators as the new denominator.88 216 1515 2301 551 66 530STEP 2Math On the SpotThe LCM of 15 and 6 is 30.Add the numerators of the equivalent fractions. Then simplify.16521 30 3030 3 2130 37 10Simplify by dividing by the GCF.The GCF of 21 and 30 is 3.Reflect14.Can you also use the LCM of the denominators of the fractions to81rewrite the difference15 - 6 ? What is the difference?Lesson 4.181

YOUR TURNPersonalMath TrainerOnline Assessmentand Interventionmy.hrw.comAdd or subtract. Write each sum or difference in simplest form.515. 16145316.-12 20517.- 3812318. 1 141019. 23 6 1520. 3 16 - 17Guided PracticeMultiply. Write each product in simplest form. (Explore Activity Example 1)1. 12 582. 35 593. 38 254. 2 38 1655. 1 45 122 56. 110Find each amount. (Example 2)7. 14 of 12 bottles of water bottles9. 35 of 40 restaurant bill 8. 23 of 24 bananas 10. 56 of 18 pencils bananaspencils511. 38 2451 12.20129- 113.20 493-14.10 14515. 3 38 1275-16. 510 18?ESSENTIAL QUESTION CHECK-IN17. How can knowing the GCF and LCM help you when you add, subtract,and multiply fractions?82Unit 2 Houghton Mifflin Harcourt Publishing CompanyAdd or subtract. Write each sum or difference in simplest form.

NameClassDate4.1 Independent PracticeCOMMONCOREPersonalMath Trainer6.NS.4Solve. Write each answer in simplest form.18. Erin buys a bag of peanuts that weighs3 of a pound. Later that week, the bag is 243full. How much does the bag of peanutsweigh now? Show your work.my.hrw.comOnlineAssessment andIntervention21. Marcial found a recipe for fruit salad thathe wanted to try to make for his birthdayparty. He decided to triple the recipe.Fruit Salad3 12 cups thinly sliced rhubarb15 seedless grapes, halved19. Multistep Marianne buys 16 bags ofpotting soil that comes in 58 -pound bags.a. How many pounds of potting soil doesMarianne buy?1 orange, sectioned210 fresh strawberries, halved3 apple, cored and diced52 peach, sliced31 plum, pitted and sliced1 cup fresh blueberries4 Houghton Mifflin Harcourt Publishing Companyb. If Marianne’s father calls and says heneeds 13 pounds of potting soil, howmany additional bags should she buy?a. What are the new amounts for theoranges, apples, blueberries, andpeaches?20. Music Two fifths of the instruments in themarching band are brass, one third arepercussion, and the rest are woodwinds.a. What fraction of the band iswoodwinds?b. One half of the woodwinds areclarinets. What fraction of the band isclarinets?b. Communicate Mathematical IdeasThe amount of rhubarb in the originalrecipe is 3 12 cups. Using what you knowof whole numbers and what you knowof fractions, explain how you couldtriple that mixed number.c. One eighth of the brass instrumentsare tubas. If there are 240 instrumentsin the band, how many are tubas?Lesson 4.183

22. One container holds 1 78 quarts of water and a second container holds5 34 quarts of water. How many more quarts of water does the secondcontainer hold than the first container?23. Each of 15 students will give a 1 12 -minute speech in English class.a. How long will it take to give the speeches?b. If the teacher begins recording on a digital camera with an houravailable, is there enough time to record everyone if she gives a15-minute introduction at the beginning of class and every studenttakes a minute to get ready? Explain.c. How much time is left on the digital camera?FOCUS ON HIGHER ORDER THINKING24. Represent Real-World Problems Kate wants to buy a new bicycle froma sporting goods store. The bicycle she wants normally sells for 360. Thestore has a sale where all bicycles cost 56 of the regular price. What is thesale price of the bicycle?26. Justify Reasoning To multiply a whole number by a fraction, you canfirst write the whole number as a fraction by placing the whole numberin the numerator and 1 in the denominator. Does following this stepchange the product? Explain.84Unit 2Work Area Houghton Mifflin Harcourt Publishing Company25. Error Analysis To find the product 37 49 , Cameron simplified 37 to 17 and4then multiplied the fractions 17 and 49 to find the product63. What isCameron’s error?

Going Further4.1COMMONCOREInterpret and computequotients of fractions, andsolve word problems involvingdivision of fractions byfractions, e.g., by using visualfraction models and equationsto represent the problem.Transforming Equations?ESSENTIAL QUESTIONEXPLORE ACTIVITY6.NS.1How can you transform a division equation intoa multiplication equation?COMMONCORE6.NS.1Dividing FractionsDivision and multiplication are opposite, or inverse, operations. A division equation canbe rewritten as a multiplication equation using the concept of fact families.32Rewrite 32 as a multiplication equation.55A What is the dividend?This will be the product, or answer, in themultiplication equation. Write the product in the last set of boxes. Houghton Mifflin Harcourt Publishing CompanyB What is the quotient, or answer, in the division equation?This willbecome one of the two factors in the multiplication equation. Write thequotient in the first set of boxes.C What is the divisor?This will become the other factor in themultiplication equation. Write the divisor in the second set of boxes.Reflect1.Analyze How does the multiplication equation compare to the correspondingdivision equation?Going Further 4.184A

Rewriting Division as MultiplicationYou can rewrite a division expression as a multiplication expression bychanging the order of the terms.EXAMPLECOMMONCORE6.NS.157Rewrite 57 as a multiplication problem.88STEP 1The dividend becomes the product, or answer,in the multiplication equation.STEP 2The divisor becomes one of the factors in themultiplication equation.STEP 3The quotient becomes the other factor in themultiplication equation.575—4 —5—788575—3 —5—788PracticeComplete the table below by using the completed equation to fill in themissing fraction in the incomplete equation.1.7 6 74 12 27 6 2 122.1 3 13 91 133.4 9 18 2 94 9 288 99 569 89 175699 105910 955107 4 1 321 43 7144.5.6.84BMultiplicationUnit 2 Houghton Mifflin Harcourt Publishing CompanyDivision

4.2Getting ReadyCOMMONCOREModeling Fraction Division?6.NS.1Interpret and computequotients of fractions, andsolve word problems involvingdivision of fractions byfractions, e.g., by using visualfraction models and equationsto represent the problem.ESSENTIAL QUESTIONHow can you model fraction division?EXPLORE ACTIVITYCOMMONCORE6.NS.1Modeling DivisionJust like division of whole numbers, one method of solving a division problemwith fractions is to make a model.Model the division expression and find the quotient.15 3A To model 15, draw 15 dots.B To model dividing by 3, circle groups ofin the model above. Houghton Mifflin Harcourt Publishing CompanyC How many circles did you draw?Therefore, 15 3 .Reflect1.Make a Conjecture Using the Explore Activity above, make a conjectureabout how to model a fraction division problem.Getting Ready 4.284C

Using Models to Divide MixedFractionsYou can use a model to show division with mixed fractions the same way youmodeled division with whole numbers.EXAMPLECOMMONCORE6.NS.1Model the division expression and find the quotient.1 233 3STEP 1Model the dividend. To model 3 13 draw four rectangles of equal size.Then shade 3 13 of the rectangles.STEP 2Circle groups of 23, which is groups of two 13 -pieces.12345There are 5 groups of 23. So, 3 13 23 5.PracticeModel each fraction division expression, then find the quotient.4 1 2.6 68 1 3.2 284DUnit 2 Houghton Mifflin Harcourt Publishing Company2 2 1. 24 4

LESSON4.2 Dividing Fractions?COMMONCORE6.NS.1Interpret and computequotients of fractions, ,e.g., by using visual fractionmodels .ESSENTIAL QUESTIONHow do you divide fractions?COMMONCOREEXPLORE ACTIVITY 16.NS.1Modeling Fraction DivisionIn some division problems, you may know a number of groups and need tofind how many or how much are in each group. In other division problems,you may know how many there are in each group and need to find thenumber of groups.A You have 34 cup of salsa for making burritos. Eachburrito requires 18 cup of salsa. How many burritoscan you make?To find the number of burritos that canbe made, you need to determine howmany 18 -cup servings are in 34 cup.Use the diagram. How many eighths34are there in 34 ? Houghton Mifflin Harcourt Publishing CompanyYou have enough salsa to makeburritos.18B Five people share 12 pound of cheeseequally. How much cheese does eachperson receive?To find how much cheese each personreceives, you need to determine howmuch is in each ofparts.How much is in each part?Each person will receivepound.Reflect1. Write the division shown by each model.Lesson 4.285

ReciprocalsAnother way to divide fractions is to use reciprocals. Two numbers whoseproduct is 1 are reciprocals.Math On the Spotmy.hrw.com312 43 14123 and 4 are reciprocals.43To find the reciprocal of a fraction, switch the numerator and denominator.numerator ·denominator 1denominatornumeratorEXAMPLE 1COMMONCOREPrep for 6.NS.1Find the reciprocal of each number.A 2992Switch the numerator and denominator.The reciprocal of 29 is 92.Math TalkMathematical PracticesHow can you checkthat the reciprocal in A iscorrect?B 1881Switch the numerator and denominator.The reciprocal of 18 is 81, or 8.C 55 5151Rewrite as a fraction.15Switch the numerator and the denominator.The reciprocal of 5 is 15.Reflect3. Communicate Mathematical Ideas Does every number have areciprocal? Explain.4. The reciprocal of a whole number is a fraction withnumerator.in theYOUR TURNPersonalMath TrainerOnline Assessmentand Interventionmy.hrw.com86Unit 2Find the reciprocal of each number.75. 86. 917. 11 Houghton Mifflin Harcourt Publishing Company2. Is any number its own reciprocal? If so, what number(s)? Justify your answer.

EXPLORE ACTIVITY 2COMMONCORE6.NS.1Using Reciprocals to FindEquivalent ValuesA Complete the table below.DivisionMultiplication6 2 37 76 7 7 25 3 58 8 35 8 8 31 5 16 6 561 6 51 1 34 3 41 3 4 1B How does each multiplication problem compare to its correspondingdivision problem?C How does the answer to each multiplication problem compare to theanswer to its corresponding division problem? Houghton Mifflin Harcourt Publishing CompanyReflect8. Make a Conjecture Use the pattern in the table to make a conjectureabout how you can use multiplication to divide one fraction by another.9. Write a division problem and a corresponding multiplication problem likethose in the table. Assuming your conjecture in 8 is correct, what is theanswer to your division problem?Lesson 4.287

Using Reciprocals to Divide FractionsDividing by a fraction is equivalent tomultiplying by its reciprocal.Math On the Spotmy.hrw.com1 14 455EXAMPLE 241 4515COMMONCORE6.NS.1Divide 59 23 . Write the quotient in simplest form.STEP 1Rewrite as multiplication, using the reciprocal of the divisor.5 2 59 329 3AnimatedMathSTEP 2my.hrw.com2The reciprocal ofis 32 .3Multiply and simplify.515 32 918 565 23 569Multiply the numerators. Multiply the denominatorsWrite the answer in simplest form.15 3 518 3 6YOUR TURNPersonalMath TrainerOnline Assessmentand InterventionDivide.911. 35 10910. 25 10my.hrw.comFind the reciprocal of each fraction. (Example 1)1. 252. 19103.3Divide. (Explore 1, Explore 2, and Example 2)4. 43 53 ?ESSENTIAL QUESTION CHECK-IN7. How do you divide fractions?8835. 45 10Unit 26. 12 25 Houghton Mifflin Harcourt Publishing CompanyGuided Practice

NameClassDate4.2 Independent PracticeCOMMONCORE6.NS.18. Alison has 12 cup of yogurt for making fruitparfaits. Each parfait requires 18 cup ofyogurt. How many parfaits can she make? Houghton Mifflin Harcourt Publishing Company Image Credits: Irochka/Fotolia9. A team of runners is needed to run a 14 -mile1relay race. If each runner must runmile,16how many runners will be needed?PersonalMath Trainermy.hrw.comOnlineAssessment andIntervention13. Jackson wants to divide a 34 -pound box oftrail mix into small bags. Each of the bags1will holdpound of trail mix. How many12bags of trail mix can Jackson fill?14. A pitcher contains 23 quart of lemonade.If an equal amount of lemonade ispoured into each of 6 glasses, how muchlemonade will each glass contain?10. Trevor paints 16 of the fence surrounding hisfarm each day. How many days will it takehim to paint 34 of the fence?15. How many tenths are there in 45 ?11. Six people share 35 pound of peanutsequally. What fraction of a pound ofpeanuts does each person receive?16. You make a large bowl of salad to sharewith your friends. Your brother eats 13 of itbefore they come over.112. Biology If one honeybee makes12teaspoon of honey during its lifetime, howmany honeybees are needed to make 12teaspoon of honey?a. You want to divide the leftover saladevenly among six friends. Whatexpression describes the situation?Explain.b. What fractional portion of the originalbowl of salad does each friend receive?Lesson 4.289

FOCUS ON HIGHER ORDER THINKINGWork Area17. Interpret the Answer The length of a ribbon is 34 meter. Sun Yi needspieces measuring 13 meter for an art project. What is the greatest numberof pieces measuring 13 meter that can be cut from the ribbon? How muchribbon will be left after Sun Yi cuts the ribbon? Explain your reasoning.918. Represent Real-World Problems Liam hasgallon of paint for painting101the birdhouses he sells at the craft fair. Each birdhouse requiresgallon20of paint. How many birdhouses can Liam paint? Show your work.19. Justify Reasoning When Kaitlin divided a fraction by 12, the result wasa mixed number. Was the original fraction less than or greater than 12 ?Explain your reasoning.121. Make a Prediction Susan divides the fraction 58 by. Her friend Robyn1651divides 8 by 32 . Predict which person will get the greater quotient. Explainand check your prediction.90Unit 2 Houghton Mifflin Harcourt Publishing Company20. Communicate Mathematical Ideas The reciprocal of a fraction less than1 is always a fraction greater than 1. Why is this?

Going Further4.2COMMONCOREInterpret and computequotients of fractions, andsolve word problems involvingdivision of fractions byfractions, e.g., by using visualfraction models and equationsto represent the problem.Real-World Division?6.NS.1ESSENTIAL QUESTIONHow do fraction division equations relate to the real world?EXPLORE ACTIVITYCOMMONCORE6.NS.1Using Division in a Real-World SituationWhen you are given a division problem, you can create a real-world situation tohelp understand what is going on in the problem. Any fractional amounts inthe problem must make sense in the real-world situation.Write a real-world situation for each division equation.A 23 3 29The equation represents the number of 3s you can divide 23 into, which is 29.A can of paint that is full is shared bypeople. Each persongets of the can of paint.B 6 13 23 9 12 Houghton Mifflin Harcourt Publishing CompanyThe equation represents the number of 23 s you can divide 6 31 into,which is.Marie is filling flower vases with water. She has a pitcher that holdscups of water, and puts cup in each vase. Marie can fillvases.Going Further 4.290A

PracticeComplete the real-world situation for each division equation.1. 34 12 1 12It takes hour to build a birdhouse. If John works for hour today,he can buildbirdhouses.3 102. 1 78 16Tom has a bottle of juice that contains-quart servings. He can pourquarts and is pouringservings.Write a real-world situation for each division equation.4. 54 12 2 1290BUnit 2 Houghton Mifflin Harcourt Publishing Company3. 12 26 13 37

Game4.2INSTRUCTIONSPlaying the GameSTEP 112One student or the teacher is the caller, andgets the caller cards. Each caller card contains afraction problem and its answer.3415471799292318891357371627494 – 225672979354529567814Each player gets a Fracto! board and 20–25 counters. The center is a freespace. Players should cover the center square before play begins.STEP 3On each turn, the caller reads aloud a problem to the players. The callerdoes not read the answer aloud.STEP 4Solve the problem read by the caller. Then search for the answer on yourFracto! board. If the answer is on your board, cover it with a counter. Houghton Mifflin Harcourt Publishing CompanySTEP 222 4 -999STEP 557172749898796729354578The caller places the card in a discard pile. Play continues until thereis a winner.Game 4.290C

Winning the GameA player who covers five squares in a row horizontally, vertically, ordiagonally says, “Fracto!” The caller uses the cards in the discard pile tocheck that this player has calculated correctly. If so, that player is thewinner. If not, play continues until someone else says, “Fracto!”2453715471816671253 Houghton Mifflin Harcourt Publishing Company!90DUnit 2

Dividing MixedNumbersLESSON4.3?COMMONCORE6.NS.1Interpret and computequotients of fractions,and solve word problemsinvolving division of fractionsby fractions .ESSENTIAL QUESTIONHow do you divide mixed numbers?COMMONCOREEXPLORE ACTIVITY6.NS.1Modeling Mixed Number DivisionAntoine is making sushi rolls. He has 2 12 cups of rice and will use 14 cupof rice for each sushi roll. How many sushi rolls can he make?A To find the number of sushi rolls that can be made, youneed to determine how many fourths are in 2 12. Use fractionpieces to represent 2 12 on the model below.114141211414141414141414B How many fourths are in 2 12? Houghton Mifflin Harcourt Publishing Company Image Credits: Stockbyte /GettyImagesAntoine has enough rice to makesushi rolls.Reflect1.Communicate Mathematical Ideas Which mathematical operationcould you use to find the number of sushi rolls that Antoine can make?Explain.2.Multiple Representations Write the division shown by the model.3.What If? Suppose Antoine instead uses 18 cup of rice for each sushi roll.How would his model change? How many rolls can he make? Explain.Lesson 4.391

Using Reciprocals to DivideMixed NumbersMath On the Spotmy.hrw.comMy NotesDividing by a fraction is equivalent to multiplying by its reciprocal. You canuse this fact to divide mixed numbers. First rewrite the mixed numbers asfractions greater than 1. Then multiply the dividend by the reciprocal of thedivisor.EXAMPLE 1COMMONCORE6.NS.1One serving of Harold’s favorite cereal contains 1 25 ounces. How manyservings are in a 17 12 -ounce box?STEP 1Write a division statement to represent the situation.17 12 1 25STEP 2You need to find how many2117groups of 12.5 are inRewrite the mixed numbers as fractions greater than 1.35 7517 12 1 25 2Rewrite the problem as multiplication using the reciprocal ofthe divisor.3535 75 5722STEP 475The reciprocal of5 is 7 .Multiply.355 5 35 5772215 5 2 125, or 12 12 2Simplify first using the GCF.Multiply numerators. Multiply denominators.Write the result as a mixed number.There are 12 12 servings of cereal in the box.Reflect92Unit 24.Analyze Relationships Explain how can you check the answer.5.What If? Harold serves himself 1 12 -ounces servings of cereal eachmorning. How many servings does he get from a box of his favoritecereal? Show your work. Houghton Mifflin Harcourt Publishing CompanySTEP 3

YOUR TURN6.Sheila has 10 12 pounds of potato salad. She wants to divide the potatosalad into containers, each of which holds 1 14 pounds. How many containersdoes she need? Explain.PersonalMath TrainerOnline Assessmentand Interventionmy.hrw.comSolving Problems Involving AreaRecall that to find the area of a rectangle, you multiply length width. If youknow the area and only one dimension, you can divide the area by the knowndimension to find the other dimension.Math On the Spotmy.hrw.comEXAMPL 2EXAMPLECOMMONCORE6.NS.1The area of a rectangular sandbox is 56 23 square feet. The length of thesandbox is 8 12 feet. What is the width?STEP 1Write the situation as a division problem.56 23 8 12STEP 2Math TalkRewrite the mixed numbers as fractions greater than 1.170 1756 23 8 12 32 Houghton Mifflin Harcourt Publishing CompanySTEP 3Rewrite the problem as multiplication using the reciprocal ofthe divisor.1701702 17 17 32310 2 1703 1720, or 6 23 3Mathematical PracticesExplain how to findthe length of a rectanglewhen you know the areaand the width.Multiply numerators. Multiply denominators.1Simplify and write as a mixed number.The width of the sandbox is 6 23 feet.Reflect7.Check for Reasonableness How can you determine if your answeris reasonable?Lesson 4.393

YOUR TURNPersonalMath TrainerOnline Assessmentand Intervention8.The area of a rectangular patio is 12 38 square meters.The width of the patio is 2 34 meters. What is the length?9.1The area of a rectangular rug is 1412 square yards.The length of the rug is 4 13 yards. What is the width?my.hrw.comGuided PracticeDivide. Write each answer in simplest form. (Explore Activity and Example 1)1. 4 14 342. 1 12 2 143 4442423. 4 1 18 4. 3 15 1 17 5. 8 13 2 12 6. 15 13 3 56 7. A sandbox has an area of 26 square feet, andthe length is 5 21 feet. What is the width of thesandbox?8. Mr. Webster is buying carpet for an exerciseroom in his basement. The room will have anarea of 230 square feet. The width of the roomis 12 12 feet. What is the length?ESSENTIAL QUESTION CHECK-IN9. How does dividing mixed numbers compare with dividing fractions?94Unit 2 Houghton Mifflin Harcourt Publishing CompanyWrite each situation as a division problem. Then solve. (Example 2)

NameClassDate4.3 Independent PracticeCOMMONCOREPersonalMath Trainer6.NS.1OnlineAssessment andInterventionmy.hrw.com10. Jeremy

Math Trainer Online Assessment and Intervention Personal my.hrw.com Math On the Spot my.hrw.com Multiplying Fractions and Whole Numbers To multiply a fraction by a whole number, you rewrite the whole number as a fraction and multiply the two fractions. Remember to use the GCF to wri