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Basic Math Skills Review. Percents. Percent. Percent (from per centum ) means per hundred or divide by one hundred. The “%” sign is used to show the number of parts per one hundred parts.
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Basic Math Skills Review Percents
Percent • Percent (from per centum) means per hundred or divide by one hundred. The “%” sign is used to show the number of parts per one hundred parts. • There is a relationship among decimals, fractions and percents. The percent sign is equivalent to the following:
Fraction/Decimal Conversions Changing a fraction to a decimal Divide the numerator by the denominator. Changing a decimal to a fraction Drop decimal and divide by the highest place value. Simplify, if possible.
Decimal/Percent Conversions Changing decimal to percent Multiply by 100 and attach percent sign. It’s the same as moving the decimal 2 places to the right. 0.375 = 37.5% Changing from percent to decimal Divide by 100. It’s the same as moving the decimal 2 places to the left. 38% = 0.38
Percent/Fraction Conversions Changing percent to fraction Drop % sign and divide by 100. Simplify if possible. Changing from a fraction to a percent Multiply by 100 and attach a % symbol.
Finding Percentage of a Quantity Percentage = Percent x Whole Quantity To find a percentage or part of a whole quantity: • Change the percent to a decimal, and • Multiply the decimal by the whole quanity.
Percentage Example A patient reports that he drank 75% of his eight ounce cup of coffee. How much coffee did he drink? 1) Change 75% to a decimal: 75% → 0.75 2) Multiply 0.75 x 8 ounces to get 6 ounces.
Word Problems • “is” means equals • “of” means multiply • “what” is the unknown whole quantity. 1) What is 20% of 75? X = 0.20 x 75 2) Ten is what percent of 15? 10 = p x 15
More Word Problems 3) Table salt (NaCl) is 40% sodium by weight. If a box of salt weighs 18 ounces, how much sodium is in the box of salt? 4) A student’s tuition bill is $17,651. Her financial aid pays 80%. How much will the student owe?
More Word Problems 5) If 1 roll of tape costs $0.69, how much do 3½ rolls costs? (Round to the nearest cent) 6) If 1 centimeter equals ⅜ inch, how many centimeters is a nail that measures 3 inches? 7) You work in a health care clinic where each employee must work 25% of 8 major holidays. How many holidays will you expect to work?
Word Problem Answers • 15 2) • 7.2 • $3530.20 • $2.42 • 8 cm • 2 holidays
NOVA Math Placement Test • The Math Placement test is given in the Testing Center. • There is a review book for the placement exam in the Annandale Library. (CG 3rd Floor) • It’s called Chart Your Success on the Compass Exam. • Brush-up on current skills, go through what you know. • Don’t try to teach yourself anything that you do not know. • Use the list of suggested websites to help you review. • Neither the Math Center nor the Tutoring Center will help you study for the exam.