OUTLINE

Overview Ratios Proportions Percents

Changing Percents to Decimals Changing Decimals to Percents

Ratios, Proportions, and Percents

Changing Percents to Fractions Changing Fractions to Percents Determining Percents

OBJECTIVES

Upon completion of this chapter, the student should be able to: 1. Distinguish the numerical relationships represented by ratios. 2. Describe the concept of proportions. 3. Explain the relationship between percents and ratios. 4. Solve for x using proportions. 5. Convert percentages into ratios and fractions, and convert ratios and fractions into percentages.

GLOSSARY

percent A fraction whose numerator is expressed and whose denominator is understood to be 100. proportion The relationship between two equal ratios. extremes The two outside terms in a ratio. means The two inside terms in a ratio. ratio A mathematical expression that compares two numbers by division.

1428344225, Pharmaceutical Calculations for Pharmacy Technicians: A Worktext, by Jahangir Moini, MD, MPH - ©Thomson

CHAPTER 3 Ratios, Proportions, and Percents

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OVERVIEW

Pharmacy technicians must understand percents, ratios, and proportions to deal with a variety of medications and treatments and to ensure accuracy in preparing and calculating these medications. Expressing percents and ratios, and how they are related to fractions and decimals, is an essential skill in order to be able to measure and calculate medications. The pharmacy technician needs to practice in order to become skilled in mathematics.

Remember

• Ratios express a relationship. • The quantities in a ratio are separated by a colon. • To change a ratio into a fraction, the first number in the ratio becomes the numerator and the second number becomes the denominator. • Ratios should be expressed in lowest terms.

RATIOS

A ratio is the relation between two numbers. Ratios may be used to relate a quantity of liquid medication to a quantity of intravenous solution....