EXT 3-6 Sampler

59 Lesson17, 6ETeacherGuide 54 Objective12: Towrite twonumbers as a ratio. To find the missing term in apair of equivalent fractions. Materials: Colored counters or cubes Vocabulary: proportion Act It Out, Draw aPicture Todaywearegoing to compare twonumbers as a fractionor ratio.A ratio compares twonumbersby division.Wewill use several differentways to finda missing term in twoequivalent ratios. Writeon theboard: Jessica ismaking lemonade for a class party. She wants to fill a large cooler bymixing1 canof lemon concentratewith3 cans ofwater.Howmany cans of waterwill sheneed for 5 cans of concentrate? Display1yellow counter (lemon) for every3 light blueorwhite (water) countersuntil a total of 15 counters representingwater aredisplayedwith a total of 5yellow (concentrate) counters. Each time say aloud the proportional parts, 1 lemonper 3waters is the same as 2 lemons per 6waters, etc. Writeon theboard: = = = = ⅓and 2/6 areequivalent ratios.Anypairof equivalent ratios is a proportion. Using thePattern Writeon theboard: 2out of every5 students in themath class are girls. If there are25 students in the class, howmany are girls? Allow students todiscussdifferentways to solve the problem. Studentsmight use classmates to act out the problem, e.g., 2girls out of 5; 4girls out of 10; 6girls out of 15; 8girls out of 20; and10girls out of 25.A student might alsodraw apictureusingX’s andO’s on theboard. Writeon theboard: = = = = 5 15 4 12 3 9 2 6 1 3 W W W L W W W L W W W L W W W L W W W L 10 25 8 20 6 15 4 10 2 5 Eachpairof equal ratios areequivalent.What is the pattern for changinga fraction toanequivalent fraction? (Multiplyordivide thenumerator anddenominator by the samenumber.) Whatnumberwouldyoumultiplyordivide5by to get thedenominatorof 25? (Multiplyby5.) Ifwemultiply thedenominatorof 5by5,wemust alsomultiply the numeratorof 2by5. Continueon theboard: Together, read the example at the topof thepage.Work problems 1, 5, 9 and13 together.Have students complete thepageon their own. Skill Builders 12-3 10 25 2 5 x 5 x 5 = 54 ©Math TeachersPress, Inc.,Reproduction by anymeans is strictly prohibited. MissingTerm inTwoEqual Ratios A ratio compares two numbers by division. The ratioof 3 to5 can also bewritten as 3:5 or 3 5 . Ingridmakes green paint bymixing3parts of bluepaint and 5parts of yellowpaint. The ratio of blue paint to yellowpaint is 3 to5or 3 5 . Howmany parts of blue paint should bemixedwith10parts of yellowpaint? blue yellow = 3 5 = Blue Yel ow l B B B y y y y y Change toequivalent ratioswith thegivendenominators. 1. 5. 9. 2. 6. 10. 3 7. 11. 4. 8. 12. ___ 16 3 8 3 4 2 7 2 5 1 8 7 10 1 5 2 3 3 4 2 5 2 3 1 2 = __ 9 = ___ 20 = ___ 14 = ___ 16 = ___ 18 = ___ 40 = ___ 25 = ___ 10 = __ 8 = __ 8 = ___ 20 = 13. There are 7 girls for every 10 students inBill’s school.What is the ratioof girls to students? If thereare100 students inBill’s school, how many aregirls? ________ ________ 15. Laurie saves $1 of every $10 she earns. At the same rate, howmuchwill Laurie save if she earns $200? ________ 14. Lindseymakes 3 free throws out of every 5attempts. Howmany free throwswill Lindseymake out of 50 attempts? ________ 16. Ona recent field trip, therewas 1 adult for every 20 students. How many adultswould be ona field trip with100 students? ________ 10 2 3 5 = 6 10 2 Think: 5 timeswhat number is 10? ...2 Multiply 3 by2 to find the missing term. 6 15 4 7:10 70girls $20 30 free throws 5adults 4 5 16 6 12 2 4 6 14 6.RP.1, 6.RP.3 MissingTerm inTwoEqual Ratios Studentsdiscover all ratiosmade from the same recipeare proportional. Grade6