Ext 6-8 Sampler

24 Grade6PartBLessonPlans: PercentofaNumberUsingProportions Lesson29, 6ETeacherGuide 82 Objective51: Touse aproportion to find thepercent or part of awhole. Materials: FractionBars (orFractionStripsmade from Master 14), PercentNumberLines (Master 24) Finding aPart of aWhole Eachpair of students or small groupwill need a set of FractionBars and a copyof PercentNumberLines to100 (Master 24). Writeon theboard: There are40 students in the art class. 25%of the students areboys.Howmanyboys are in the class? Ask students to read theproblem anduse apicture to solve theproblem. Pictures and solutionswill vary.One possible solution: X X X X X X X X X X Explanation: If 25% areboys, 1out of every4 students areboys. Imarked anXon1out of eachgroupof 4. There were25X’s. You canalsouse fractionbars tovisualize the whole-part relationships.What colorbarswould youuse for25%? (bluebars) Writeon theboard: Whatdoes thispicture showus? (The shaded part shows theboys in the art class.) We can setupa proportion from thispicture.Weknow that 25%means 25partsout of 100, and that 100 is thewhole. Writeon theboard: Ifwe let x stand for thenumberof boys,where should wewrite x ? (xgoes above thebar because it is thepart of a whole.) Where shouldwewrite40? (40goes below thebar because it represents thewhole class.) Howdowe solve thisproportion? (Use the cross productsmethod.) 25 (parts) 100 (whole) 40 (whole class) x (part boys) = 25 (parts) 100 (whole) %boys 0% 0 n 40 25% 100% thewhole art class Writeon theboard: There is anotherway to solve thisproportion usingequivalent fractions. Firstwe reduce the fraction ifpossible.Nextmakeboth ratioshave the same denominator.Whatnumberdoyoumultiplyby4 to get 40? (10) Wewillmultiply the fractionby 10⁄10,which is the sameasmultiplyingbyone. Writeon theboard: Complete the example at the topof thepagewith the class. For questions 5 to10, have students identifywhich numbers represent parts andwhich represent thewhole. Skill Builders 51-1, 51-2, 51-3, 51-5 25 100 40 x = 1 4 40 x 40 10 x = 10 1 4 = 40 x = = 10 10 25 100 40 x 25 40 = 100 x 1000 = 100 x 10 students = x = 82 ©Math TeachersPress, Inc.,Reproduction by anymeans is strictly prohibited. Percent of aNumber UsingProportions Hector got 75%on hismath test. There were60problems on the test. How many questions didhe get correct? 75% as a ratio= 75 100 part correct whole 75 100 n 60 100 n 75 60 100 n 4500 n 45 Hector got ____ questions correct. 75 100 n 60 1. 40___ 100 = n __ 60 ______________ 3. 16___ 100 = n __ 50 ______________ 2. 30___ 100 = n __ 150 ______________ 4. 15___ 100 = n __ 160 ______________ 5. Shawngot 80%onhismath test. Therewere 50problems on the test. Howmany didShawn get correct? _______ 7. 20% of the students bring their lunch to school. If thereare45 students in the school, howmany bring their lunches? _______ 9. Drewmade45% of his free throw attempts. If he tried200 free throws, howmany didhemake? _______ 6. Vernon got 84% correct on hismath test. Therewere 25questions on the test. Howmany questions did he get correct? _______ 8. Vicki got 60%on a social studies test. The test had 60 problems. Howmany problems didVicki get correct? _______ 10. Leahgot 65%of theproblems correct on a science test. Therewere40 problems on the test. Howmany problems did she get correct? _______ Solve for n . Write theproportion andsolve. 60 whole 0% 75% 100% part You canuseaproportion tosolve thisproblem. Should the60 bewrittenabove or below the fraction bar? Is 60 thewhole testorpart of the test? Letn represent thenumber correctoutof60. Crossmultiply. Divide both sides by 100. Part B 40problems 9students 90 free throws 21 questions 36problems 26problems n=24 n=45 n=8 n=24 45 6.RP.3, 6.RP.3c Grade6