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Fractions, Decimals, and Percents
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Video Support http://www.learnalberta.ca/content/mesg/html/math6web/index.html?page=l essons Learn Alberta: percents
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4.1 Connect Fractions, Decimals, and Percents
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Student Objective: After this lesson, I will be able to… Estimate percents as fractions or as decimals Compare and order fractions decimals, and percents Estimate and solve problems involving percent
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Student Objective: I will be able to problem solve using percents from 1%-100% Percent Student Objective: I will be able to problem solve using percents from 1%-100% What does it mean?? “out of 100” Ex: 20 out of 100 or 20% or 20 or 0.20 100 “of” means x
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Student Objective: I will be able to problem solve using percents from 1%-100% Percent Student Objective: I will be able to problem solve using percents from 1%-100% Ex: 64% = 64 = 0.64 100 Ex: 91% = = Ex: 37% = = Bonus Ex: 107% = =
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Think Money $0.25 ¼ of a dollar 25% of a dollar $0.50 ½ of a dollar 50% of a dollar $0.10 1/10 of a dollar 10% of a dollar
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“Friendly” Percents Discuss with your partner What are FRIENDLY percent numbers “percentages” to work with? and why?
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“Friendly” Percents 25% 50%75% 100%
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Student Objective: I will be able to problem solve using percents from 1%-100% Friendly Percent Numbers Student Objective: I will be able to problem solve using percents from 1%-100% What is 25% of $10.00? = What is 50% of $10.00? = What is 75% of $10.00? = What is 100% of $10.00? = What strategy did you use to solve this problem?
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Student Objective: I will be able to problem solve using percents from 1%-100% Find a Percent of a Number Student Objective: I will be able to problem solve using percents from 1%-100% Question: Before you start make a good estimation 4 brothers bought their mother a birthday present for $84.60. They each paid 25% of the bill. How much was each brother’s share?
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Solution #1 Find 50% of $84.60. 50% of $84.60 is half of $84.60 Half of $84.60 is $42.30 Now find 25% of $84.60 25% is half of 50% Half of $42.30 is $21.15 Check: $21.15 x 4 = $84.60 Each brother’s share is $21.15 $84.60 ÷ 2 = $42.30 $42.30 ÷ 2 = $21.15
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Solution #2 Why divide by 4? $84.60 $20$20$20$20 $1$1$1$1 $0.15$0.15$0.15$0.15 Check: $21.15 x 4 = $84.60 Each brother’s share is $21.15 $84.60 ÷ 4 = $21.15
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On Your Own… Question: Before you start make a good estimation Ten co-workers are buying Kayden a going away present and will each pay 10%. They decide to buy him a backpack for $92.30. How much should each pay?
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Answer Find 10% of $92.30. Recall that 10% = 10/100 = 1/10 10% of $92.30 is one tenth of $92.30 One tenth of $92.30 is $9.23 Each co-worker should pay $9.23 $92.30 ÷ 10 = $9.23
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Apply What You Know Student Objective: I will be able to problem solve using percents from 1%-100% Discuss with your partner Use mental math to find each percent. A) 90% of 16 B) 60% of 90 C) 40% of 80 What strategies did you use?
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“UnFriendly” Percents Discuss with your partner What are UNFRIENDLY percent numbers “percentages” to work with? and why?
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“UnFriendly” Percents 17%, 93%, 77%, 33%, 54%....... So how do you work with these percents? You must convert the percent to a decimal then multiple
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“UnFriendly” Percents Ex: 28% x 60 = 28% = 28 = 0.28 0.28 x 60 = 100 Ex: 52% of 118 “of” means X Ex: 7% of 242
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Student Outcome: I will be able convert %’s, decimals and fractions Apply What You Know Student Outcome: I will be able convert %’s, decimals and fractions Discuss with your partner Compare ¾, 70%, and 0.72 Put them in order from smallest to biggest (ascending) Put them in order from largest to smallest (descending) What strategies did you use?
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Solution ¾ = 0.75¾ = 75% 70% = 0.70OR70% = 70% 0.72 = 0.720.72 = 72% Converted to decimalsConverted to percents 0.70 < 0.72 < 0.75 = ascending 0.75 > 0.72 > 0.70 = descending
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Compare Fractions, Decimals, and Percents. Solution: Convert all the numbers to decimals, or fractions or percents.
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Student Outcome: I will be able convert %’s, decimals and fractions Show What You Know… Student Outcome: I will be able convert %’s, decimals and fractions A) 56%, 0.48, ½ (place in ascending order) B) 35%, 39/100, 0.36 (place in descending order)
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Assignment Page 129 #5ac, 6ac, 8ab, # 9ab, 10ab, 11 #12ab, 13ab, 14a, #20, 21, 24, Extend #28, 29
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Practical Quiz #1 Question #1 25% of $50.00 Question #2 Find 10% of $72.40
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4.2 Fractions, Decimals, and Percents Math Links page 132
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Objective After this lesson I will be able to… Convert between fractions, decimals, and percents Estimate percent values Distinguish between terminating and repeating decimals Relate fractions to terminating and repeating decimals.
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Example Look at the following hockey statistics Which goalie is having the best save percentage? Why? GoalieShots on Goal SavesSave % Decimal Save % M. Kiprusoff673606 M. Vernon586545 P. Reddock797726 T. Bunz709658
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Using Your Table Goalies can be rated on “save percentages.” This statistic is the ratio of saves to shots on goal. Save Percentage = Number of Saves Shots on Goal
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Extending Your Thinking!! Using our chart, decide which goalie is having the best season. Is it better to have a higher or lower save percentage? How are the decimal and fraction forms of the save percentage related? Which form is more useful? Why?
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Convert Fractions to Decimals and Percents TeamWinsLossesWinning % (Decimal) Winning % Miami5923 New Jersey4240 Los Angeles3448 Team Percentage = Number of wins Total game played
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Student Outcome: I will be able convert %’s, decimals and fractions On Your Own Student Outcome: I will be able convert %’s, decimals and fractions A) What is the team percentage for each team? (leave answer as a fraction) B) Change each fraction to a decimal number rounded to the nearest thousandth C) Use your rounded decimal value to show the approximate percent value for each team
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Solution A Total Games = wins + losses Miami: Total Games = 59 + 23 =82 Team Percentage = 59/82 New Jersey: 42 + 40 = 82 Team Percentage = 42/48 Los Angeles: 34 + 48 = 82 Team Percentage = 34/82
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Solution B Convert each fraction to a decimal. Miami: 59/82 = 0.720 New Jersey: 42/82 = 0.512 Los Angeles: 34/82 = 0.415
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Solution C To convert to a percent, multiply the decimal by 100 Miami: 0.72 x 100% = 72% New Jersey: 0.512 x 100% = 51.2% Los Angeles: 0.415 x 100% = 41.5%
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Assignment Page 137 #5ab, 6ab, 7
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Practical Quiz #2 Fill in the chart EventFractionDecimalPercent 30% off DVD’S Tip is 12% Exam Mark is 86%
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Student Outcome: I will be able convert %’s, decimals and fractions 4.2 Change Fractions to Repeating Decimals Student Outcome: I will be able convert %’s, decimals and fractions What is a Repeating Decimal? A decimal number with a digit or group of digits that repeats forever Repeating decimals are shown with a bar Ex: 1=0.33333=0.3 3 Ex: 5=0.833333=0.83 6 Learn Alberta: Repeating Decimals http://www.learnalberta.ca/content/memg/index.html?term=Division03/Repeating_Decimal/index.html
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Student Outcome: I will be able convert %’s, decimals and fractions Using a Calculator Student Outcome: I will be able convert %’s, decimals and fractions Change the following fractions into a repeating decimal. A) 1/3 = B) 5/9 = C) 5/6=
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On Your Own Assignment Page 138 #8ab, 9ab, 10ab, 11ab Extend #21
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Student Outcome: I will be able to make estimations using %’s 4.2 Estimate Percents Student Outcome: I will be able to make estimations using %’s Ex: Paige has answered 94 questions correctly out of 140 questions. Estimate her mark as a percent.
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Student Outcome: I will be able to make estimations using %’s Solution Student Outcome: I will be able to make estimations using %’s Think: What is 50% of 140? Half of 140 is 70 Think: what is 10% of 140? 140 ÷ 10 = 14 50% + 10% = 60% of 140 70 + 14 = 84 50% + 10% + 10% = 70% of 140 70 + 14 + 14 = 98 The answer is between 60% and 70%, but closer to 70% TOO LOW TOO HIGH
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On Your Own… Assignment Page 138 #12, 13
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Assignment: Let’s go shopping You have $1000.00 to spend for Christmas. From magazines you will cut out 10 items that are on sale and total your cost including Gst 5% Items will be glued to a piece of paper with a “formal” bill attached.
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Assignment: Let’s go shopping
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Student Outcome: I will learn about terminating decimals and how to convert them to fractions. 4.2 Change Terminating Decimals Into Fractions Student Outcome: I will learn about terminating decimals and how to convert them to fractions. What is it… Terminating Decimal A decimal number in which the digits stop Examples include 0.4, 0.86, 0.125
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Student Outcome: I will learn about terminating decimals and how to convert them to fractions. Terminating Decimal Numbers into Fractions Student Outcome: I will learn about terminating decimals and how to convert them to fractions. Question: A) What fraction of a dollar is $0.75? B) Change 0.652 to a fraction
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Solution A) The decimal number 0.75 is a terminating decimal. The last digit is in the hundredths place, so the denominator is 100. 0.75 = 75 100 So, $0.75 is 75/100 of a dollar or ¾ of a dollar $0.75 is 75¢ Or, 3 quarters
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How would we say each decimal and write it as a fraction? Ex #10.123 Ex #20.056 Ex #30.009 Ex#40.450 Ex #514.773 (Bonus)
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Key Ideas To change a fraction to a decimal number, divide the numerator by the denominator. Ex: 3/8 = 3 ÷ 8 = 0.375 Repeating decimal numbers can be written using a bar notion Ex: 1/3 = 0.333… = 0.3 To express a terminating decimal number as a fraction, use place value to determine the denominator 0.9 = 9/100.59 = 59/1001.463 = 1463/1000
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Assignment Page 138-139 #14ab, 15ab, 16, 19
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Application of Percents Assignment Page 143-144 # 6, 8, 10, 13, 16, 17 Extend #19, 21, 22
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Game – Page 150
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