A Review of Arithmetic Jeanelle F. Jimenez RN, BSN, CCRN Chapter 6 A Review of Arithmetic Jeanelle F. Jimenez RN, BSN, CCRN Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

Roman Numerals I = 1 V = 5 X = 10 L = 50 C = 100 D = 500 M = 1000 Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

Roman Numerals (cont’d) Add numerals when a smaller numeral follows a larger numeral Subtract numerals when a smaller numeral precedes a larger one Examples VI = 6 VII = 7 XC = 90 Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

Fractions Numerator Denominator Reducing to lowest terms Addition, subtraction, multiplication, division Fractions as decimals Cancellation Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

Decimal Fractions Decimal places Prescriptions may use a slash (/) instead of a decimal point 1 mg = 0.001; g = 0/001 g Multiplying decimals Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

Percents Percent means per 100 Changing percents to fractions 25% = 25/100 = 1/4 Changing percents to decimal fractions 5% = 0.05 24% = 0.24 Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

Ratios A ratio is the relationship one quantity bears to another Changing ratio to percent 6:1 = 6/1 x 100 = 600% Changing percent to ratio Simplifying ratios 25:100 = 1:4 or 25/100 = 1/4 Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

Systems of Weights and Measures Household measurements Apothecary measurements Metric system Conversion of metric units Calculations that do not require conversions Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

Calculation of IV Fluid and Medication Administration Rates IV fluid orders Solvent and solutes Drip chambers Rounding Volumetric and nonvolumetric pumps Calculation of flow rates Number of mL ÷ Number of hours = mL/hr Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

Fahrenheit and Centigrade (Celsius) Temperatures Formula for converting Fahrenheit to centigrade temperature (Fahrenheit – 32) x 5/9 = centigrade Formula for converting centigrade temperature to Fahrenheit temperature (centigrade x 9/5) + 32 = Fahrenheit Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

Ratio Proportion vs Formula Method Mosby items and derived items © 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.