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Published byLawrence Wilkins Modified over 9 years ago
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What is a ratio? ThinkWriteShare
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A ratio is…. n A comparison of two numbers. n It can be written several ways n As a fraction n Using a colon n Using the word to
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Let’s find the ratio of girls to boys in the class n Write it three ways on your dry board n What is the ratio of teachers to students in the class? n Write it three ways on your dry board!
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Remember to always simplify- yes- even a ratio can be simplified!! n Express each ratio as a fraction in simplest form: n 4 goals to 10 attempts n 2/5
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Express each ratio as a fraction in simplest form: n 15 dimes out of 24 coins n 15/24 n 5/8
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Express each ratio as a fraction in simplest form: n 4 weeks to plan 2 events n 4/2 n 2/1
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What if… n You are comparing units? n What is a unit? n Think n Write n Share
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n 3 feet to 16 inches n We must first convert our larger units into smaller units. n How could we change feet into inches? n Think, Write, share
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n Multiply 3 feet by 12, because there are 12 inches in 1 foot. 3 feet (12) = 36 inches 16 inches 16 inches Don’t forget to simplify! 36/16 = 9/4
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Try some on your dry board: n 11 gallons to 11 quarts n Change gallons to quarts. n How many quarts are in a gallon? n 1 gallon = 4 quarts 11gallons (4 ) =44 quarts 11 quarts 11 quarts 44/11 = 4/1
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Try: n 18 miles to 18 yards n How many yards are in a mile? n 1760 yards = 1 mile 18 miles(1760) = 31680 yards 18 yards 18 yards 31680/18= 1760/1
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Try: n 10 inches to 3 feet n 12 inches = 1 foot 10 inches = 10 inches 3 feet (12) 36 inches 10/36= 5/18
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Ratios….. n Pass out WS 375 n Students will complete numbers 1-12 on own n Pass out talking slips n Students will pass out to group
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Talking slips n The number on your talking slip is the number of the problem you will be explaining to your team. n You do not have to go in order n Who ever places their talking slip in the center of the table is the ONLY PERSON SHARING n Others may agree or disagree with your answer. n When all questions have been answered place your slips back in the baggy!
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What is a rate? n Think n Write n Share
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A rate…. n A ratio of two measurements n They have different kinds of units n Examples: n Miles/gallon n Dollars/pound
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Can you think of any more examples of rate? n Write them on your dry board. n Share with your team n Share with the class
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What is a unit rate? n Think n Write n Share
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A unit rate is when a rate is simplified so the denominator is equal to one. n 18 dollars/ 20 CDS n How much is 1 CD? n To find the unit rate divide both the numerator and the denominator by the denominator!
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18 dollars ÷ 20 = 0.9 20 CDS ÷ 20 = 1 Each CD costs 0.90 cents each!
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Try some on your dry board: n Find the unit rate for each rate: n $3 dollars for 6 cans of tuna. n To find the unit rate I want to find out how much one can costs. n Divide the numerator and denominator by 6. $3 ÷ 6 = 0.5 1 can of tuna is 0.50 cents 6 ÷ 6 1 6 ÷ 6 1
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Try: Find the unit rate n 140 miles on 6 gallons 140 miles ÷ 6 = 23.33 miles 6 gallons ÷6 1 gallons 6 gallons ÷6 1 gallons 23.3 miles/gal
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Try: Find the unit rate: n 25 feet in 3.2 hours 25 feet ÷ 3.2 = 7.8125 feet 3.2 hours ÷ 3.2 1 hour 7.8125feet/hr
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You will get a WS n Put your name on the top n You will solve a problem n When you hear the buzzer, rotate papers n Simultaneous Roundtable
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