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Test: Monday Have out Paper, pencil, and calculator Make sure you try the bonus When finished: work on something quietly on your own!! When finished: work on something quietly on your own!!
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CONVERTING FRACTIONS, DECIMALS AND PERCENTS Standards: 7.RP.2, 7.RP.3 Analyze proportional relationships and use them to solve real-world and mathematical problems
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Fractions Decimals Percents ¼.25 25%
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SAME VALUE DIFFERENT FORMS A same value can be written in different forms. For example: ½ fraction.5 decimal 50% percent
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FRACTIONS Fractions can be converted into other forms… DECIMALS PERCENTS Numerator Denominator DIVIDE MULTIPLY BY 100 OVER 100 Percent 100
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Convert a Fraction into a Decimal
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CONVERT A DECIMAL INTO A PERCENTAGE Multiply the decimal by 100: 0.25 x 100 = 25% Example: 0.625 = **Multiplying by 100 moves the decimal two places right. Be sure to add the % sign.
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Convert a Percent to a Fraction
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PRACTICE
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FINDING PERCENTS USING PROPORTIONS Standards: 7.RP.2, 7.RP.3 Analyze proportional relationships and use them to solve real-world and mathematical problems
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PROPORTIONEXAMPLE
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EXAMPLES
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HOMWORK Due Friday
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PERCENT EQUATION Standards: 7.RP.2, 7.RP.3 Analyze proportional relationships and use them to solve real-world and mathematical problems
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PRACTICE Part = % (in decimal form) x whole
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PERCENT CHANGE Standards: 7.RP.2, 7.RP.3 Analyze proportional relationships and use them to solve real-world and mathematical problems
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WHOLE-CLASS EXAMPLE Find the change: 2.95 – 1.30 = 1.65 Set up ratio: change 1.65 original 1.30 Convert fraction to decimal: 1.269 Convert decimal to % 126.9% 126.9% INCREASE IS REASONABLE THE PRICE MORE THAN DOUBLED!!
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INDIVIDUAL EXAMPLE Find the change: 280 – 220 = 60 Set up ratio: change 60 original 280 Convert fraction to decimal.214 Convert decimal to % 21.4%
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PERCENT ERROR Standards: 7.RP.2, 7.RP.3 Analyze proportional relationships and use them to solve real-world and mathematical problems
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WHOLE-CLASS EXAMPLE Find the error: 15 – 13.5 = 1.5 Ratio of Error 1.5 Actual 15 Convert to Decimal:.1 Convert to % 10%
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INDIVIDUAL EXAMPLE Find the error: 13.75 – 10 = 3.75 Ratio of Error 3.75 Actual 13.75 Convert to Decimal:.272 Convert to % 27%
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HOMWORK Due Friday
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SALES TAX AND TOTAL COST Standards: 7.RP.2, 7.RP.3 Analyze proportional relationships and use them to solve real-world and mathematical problems
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WHOLE-CLASS EXAMPLE Tax = 0.055 x 42 Tax = 2.31 42 + 2.31 = Total Sweatshirt + tax = total 42 + 2.31 = $44.31
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WHOLE-CLASS EXAMPLE Total cost = 1.055 x 42 Total cost = $44.31 100% + 5.5% 1.055
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INDIVIDUAL EXAMPLE 2.95 x 1.05 = $3.10 28 x 1.15 = $32.20 $30 100% Tip 20% Tax 5.75% 125.75% 1.2575 x 30 = $37.73
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TIPS AND MARKUPS Standards: 7.RP.2, 7.RP.3 Analyze proportional relationships and use them to solve real-world and mathematical problems
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WHOLE-CLASS EXAMPLE Method 1: 15 x.2 = 3 15 + 3 = $18 Method 2: 15 x 1.2 = $18
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INDIVIDUAL EXAMPLE $42 100% tax 6% Tip 20% Total 126% 1.26 x 42 = $52.92
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SALE PRICE AND ORIGINAL PRICE Standards: 7.RP.2, 7.RP.3 Analyze proportional relationships and use them to solve real-world and mathematical problems
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WHOLE-CLASS EXAMPLE $15.50 at 25% discount means a person will pay 75% 15.50 x.75 = 11.625 $11.63 Now add tax 11.63 x 1.065 = $12.39
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INDIVIDUAL EXAMPLE $239.89 was 30% discount a person will paid 70% If 239.89 is 70% what was 100%? 239.89 = 70% x 100% x = $342.70
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SIMPLE INTEREST FORMULA Standards: 7.RP.2, 7.RP.3 Analyze proportional relationships and use them to solve real-world and mathematical problems
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WHOLE-CLASS EXAMPLE Interest = Principal x Rate x Time I = 1,560 x 0.025 x 3 I = $1,170 That means Jenny had a total of (1560 + 1170) $1,170 In her savings account at the end of 3 years
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INDIVIDUAL EXAMPLE Interest = Principal x Rate x Time I = 760 x 0.04 x 5 I = $152 That means Marcos had a total of (760 + 152) $912 In his savings account at the end of 5 years
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HOMWORK Due Friday
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BELLWORK
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REVIEW PERCENTS GAME Standards: 7.RP.2, 7.RP.3 Analyze proportional relationships and use them to solve real-world and mathematical problems
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X-FACTOR GAME
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