1. Chapter 8 Mathematical Calculations Used in Pharmacology Copyright © 2013, 2010, 2006, 2003, 2000, 1995, 1991 by Mosby, an imprint of Elsevier Inc. 1

2. Learning Objectives  Compare the units used in the apothecary, metric, and household measures systems  Use the apothecary system to convert from one measure to another  Use the metric system to convert from one measure to another 2 Copyright © 2013, 2010, 2006, 2003, 2000, 1995, 1991 by Mosby, an imprint of Elsevier Inc.

3. Learning Objectives (cont.)  State the values of common household measures and their equivalents  Use common abbreviations and symbols to interpret and solve medication problems 3 Copyright © 2013, 2010, 2006, 2003, 2000, 1995, 1991 by Mosby, an imprint of Elsevier Inc.

4. Overview Three systems of weight and measure:  Household  Apothecary  Metric 4 Copyright © 2013, 2010, 2006, 2003, 2000, 1995, 1991 by Mosby, an imprint of Elsevier Inc.

5. Apothecary System  Grains: gr (solids)  Minim: m (liquids); Box 8-1 (dram and ounce)  Lowercase Roman numerals  Common fractions 5 Copyright © 2013, 2010, 2006, 2003, 2000, 1995, 1991 by Mosby, an imprint of Elsevier Inc.

6. Metric System  Decimal system  Meter: m (length)  Liter: L (volume)  Gram: g (weight)  Box 8-2 6 Copyright © 2013, 2010, 2006, 2003, 2000, 1995, 1991 by Mosby, an imprint of Elsevier Inc.

7. Metric System (cont.)  Converting  Arabic numerals and decimal fractions  Move decimal place to the right or left  Metric prefixes 7 Copyright © 2013, 2010, 2006, 2003, 2000, 1995, 1991 by Mosby, an imprint of Elsevier Inc.

8. Metric and Apothecaries’ Equivalents  Conversion – fractions  Rounding  Approximate Equivalents (Box 8-3)  Rules for Converting Between Apothecaries’ and Metric System (Box 8-4) 8 Copyright © 2013, 2010, 2006, 2003, 2000, 1995, 1991 by Mosby, an imprint of Elsevier Inc.

9. Household Measures  Liquid measure  Arabic numerals  Common Household Measures (Box 8-5)  Rough equivalents to metric and apothecaries’ systems  Conversions Among Household, Apothecary, and Metric Systems (Table 8-2, Box 8-6) 9 Copyright © 2013, 2010, 2006, 2003, 2000, 1995, 1991 by Mosby, an imprint of Elsevier Inc.

10. Converting Temperature Readings  Fahrenheit  Celsius  Formulas to convert 10 Copyright © 2013, 2010, 2006, 2003, 2000, 1995, 1991 by Mosby, an imprint of Elsevier Inc.

11. Question 1 Which system uses grains for solids and minims for liquids? 1. Arabic system 2. Apothecaries’ system 3. Roman system 4. Metric system 11 Copyright © 2013, 2010, 2006, 2003, 2000, 1995, 1991 by Mosby, an imprint of Elsevier Inc.

12. Question 2 50 mcg = __________ mg. 1. 500 2. 5000 3. 0.05 4. 0.005 12 Copyright © 2013, 2010, 2006, 2003, 2000, 1995, 1991 by Mosby, an imprint of Elsevier Inc.

13. Question 3 A patient weighs 198 pounds. How much is this in kilograms? 1. 98 kg 2. 90 kg 3. 108 kg 4. 88 kg 13 Copyright © 2013, 2010, 2006, 2003, 2000, 1995, 1991 by Mosby, an imprint of Elsevier Inc.