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Percent. Ms. Crusenberry 9-2013. Vocabulary. Percent % - part per one hundred Rate – percent Base – the amount you are taking a part of percent of Percentage – result obtained by multiplying a number by a percent. Changing Percents to Decimals and Fractions.
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Percent Ms. Crusenberry 9-2013
Vocabulary • Percent % - part per one hundred • Rate – percent • Base – the amount you are taking a part of percent of • Percentage – result obtained by multiplying a number by a percent
Changing Percents to Decimals and Fractions Remember your place value decimal chart 24% = .24 or 24/100 6% = .06 or 6/100 Simplify - 6/25 3/50
How to Change a Percent to a Decimal • To change a percent to a decimal, move the imaginary decimal to places to the left and drop the percent sign Ex. 1 3. % **there is always an imaginary decimal behind every whole number. Move it two places to the left and drop the percent sign. So, 13.% = .13
What if???? • You had just 5%? In order to move the imaginary decimal two places to the left, you will have to add a zero (0) in front of the 5.0 5 .% = .05
Practice Change the following to both a decimal and a fraction. • 13% • 7% • 68% • 120%
Answers • .13 13/100 • .7 7/10 • .68 68/100 17/25 • 1.20 1 20/100 1 1/5
Renaming Fractions and Decimals as Percents • To rename a fraction as a decimal, divide the numerator by the denominator .75 Ex. ¾ = 4 3.00-2 8 20- 20 0 • Now to make it a %, move the decimal two places to the right. This equals 75%
Vocabulary • Rate – percent • Base – the amount you are taking a part or percent of • Percentage – result obtained by multiplying a number by a percent 20% of 80 is 16 rate base percentage
Finding the Is • There are two ways to do this.First is the is/of = %/100 formulaSecond is to change the percent to a decimal and then multiply it by the of Ex. 28% of 62 is what number .28 x 62 = 17.36 the formula is on the next slide….
Formula is = % of 100 x = 3 45 100 100x = 135 100 100 x = 1.35
Practice Use whichever way you are comfortable with!! • 22% of 36 is ____? • 7% of 48 is _____? • 3.2% of 15 is _____? • 36% of 36 is _____?
Answers • 7.92 • 3.36 • .48 • 12.96
Finding the Of • There are two ways to do this.First is the is/of = %/100 formulaSecond is to change the percent to a decimal and then divide the is by the decimalEx. 25% of what number is 12? 12 ÷ .25 = 48 the formula is on the next slide….
Formula is = % of 100 12 = 25 x 100 1200 = 25x 25 25 x = 48
Practice Use whichever way you are comfortable with!! • 22% of _____ is 17.6 • 45% of ____ is 80.55 • 5% of _____is 92. • 1.3% of _____ is 60.
Answers • 80 • 179 • 1840 • 4615.38
Finding the % • There are two ways to do this.First is the is/of = %/100 formulaSecond is to divide the is by the ofEx. _____ of 17 is 1.02? 1.02 ÷ 17 = .06 = 6% the formula is on the next slide….
Formula is = % of 100 1.02 = x 17 100 102 = 17x 17 17 x = 6 = .06 = 6%
Practice Use whichever way you are comfortable with!! • _____ % of 18 is 2.7 • _____% of 45 is 9 • _____ % of 200 is 120 • _____ % of 70 is 10.5
Answers • 15% • 20% • 6% • 15%
Problem Solving • You receive 7/8 of the votes cast. What percent of the votes do you receive? • You correctly answer 32 problems out of 35 problems on a test. What percent of the problems does he get correct? • An advertisement claims that seven out of ten doctors recommend Brand A aspirin. What percent of the doctors recommend the aspirin?
Continued…. • A test has 50 questions. You get 90% correct. How many questions did you get correct? • The team plays 60 games. They win 30%. How many do they win? • 35 students are in class. 60% are girls. How many are girls? How many are boys?
Continued… • 75% of the buses have arrived. 48 have arrived. How many buses are there in all? • 80% of the students vote. 48 students vote. How many students are there in all? • You lose 32% of your beads. You lost 24 beads. How many beads did you have to begin with?
Continued… • 40 students are in the class. 18 students go on the field trip. What percent go on the field trip? • The total distance is 52 miles. Sue drives 13 miles. What percent of the distance does she drive? • Gary attempts 84 shots. He makes 63. What percent of the shots does he make?
Answers • 7 ÷ 8 = 88% • 32 ÷ 35 = 91% • 7 ÷ 10 = 70% • .90 x 50 = 45 • .30 x 60 = 18 • .60 x 35 = 21, 14 are boys • 48 ÷ .75 = 64 • 48 ÷ .80 = 60 • 24 ÷ .32 = 75 • 18 ÷ 40 = 45% • 13 ÷ 52 = 25% • 63 ÷ 84 = 75%