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Chapter 5. Equivalents and Percents. Percent. Percent means “per centum” or “per hundred” or /100. 28 = 28%, 396 = 396%, .9 = .9 % 100 100 100. 1. Write 156 as a percent 100.
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Chapter 5 Equivalents and Percents
Percent • Percent means “per centum” or “per hundred” or /100. • 28 = 28%, 396 = 396%, .9 = .9 % 100 100 100
Going from Percent to Decimal • Move the decimal point 2 places to the left then drop the % sign • 72% = .72 • .25% = .0025 • 124% = 1.24 • 2% = .02
Going from Decimal to Percent • Move the decimal point 2 places to the right then add the % sign (move to the % sign) • .24 = 24% • .024 = 2.4% • .0024 = .24% • 1.25 = 125%
Changing a Percent to a Fraction • Change to a decimal first, then write as a fraction and simplify. • 37% = .37 = 37 , 75% = 75 = 3 100 100 4 43.5% = .435 = 435 = 87 1000 200 325% = 3.25 = 3 25 = 3 1 100 4
Changing a Percent to a Fraction • If the percent contains a mixed number, change the mixed number into an improper fraction and multiply by 1/100. Simplify. • 3 3/8% = 27/8 x 1/100 = 27/800 • 16 7/8% = 135/8 x 1/100 = 135/800 = 27/100
Changing a Fraction to a Percent • Change the fraction to a decimal, then change the decimal to a percent. .375 • 3/8 = 8 3.000 .375 = 37.5% 24 60 56 40 40 0
Changing a Fraction to a Percent • Change the fraction to a decimal, then change the decimal to a percent. 7/40 = .175 = 17.5% 39/50 = .78 = 78% • If a decimal repeats infinitely, round off to nearest hundredth of a percent. 1/6 = .16666… ≈ .1667 = 16.67%
Equivalents • Change from fraction to decimal to percent, given one form
17. Change 27.5% to an equivalent A) fraction reduced to lowest termsB) decimal
18. Change 0.825 to an equivalent A) fraction reduced to lowest termsB) percent
20. Change to a common value and put in order from smallest to largest. 3/16 .17 20%
21. Change to a common value and put in order from smallest to largest. 15/25 59/100 61 2/3% .62
Solving Percent Problems with the Equation Method • Note the mathematical equivalent for the following words.
Solving Percent Problems with the Equation Method • What is 5% of 19? N = 5% x 19 N = .05 x 19 N = .95 Find 160% of 500 N = 160% x 500 N = 1.60 x 500 N = 800
Solving Percent Problems with the Equation Method • 12 is 0.6% of what? 12 = 0.6% x N 12 = .006 x N 12 = .006 x N .006 .006 2000 = N What percent of 5000 is 3.8? N x 5000 = 3.8 N x 5000 = 3.8 5000 5000 N = .00076 N = .076%
Solving Percent Problems with Proportion Method • a/b = p/100 a = amount b = base p = percent number Note “a” is associated with “is” It’s on the top “b” is associated with “of.” It’s on the bottom. Remember a, e, i, o, u: i before o
Solving Percent Problems with Proportion Method Note “a” is associated with “is” “b” is associated with “of” What is 52% of 300? is = p of 100 N = 52 300 100
Identify p b a 25. What is 60% of 70 26. 68 is what percent of 72? 27. 354 is 40% of what number?