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Introductory Pharmacology - Fractions Ann MacLeod, RN, BScN, MPH Objectives Convert Roman Numerals to Arabic Convert Arabic to Roman Numerals Compare the size of fractions Add and subtract fractions Divide and Multiply fractions Reduce fractions to the lowest terms Roman Numerals 1/2 1 2 3 4 5 6 7 8 9 ss I, id II ii III iii IV iv V v VI vi VII vii VIII viii IX ix 10 11 15 20 30 50 100 X XI XV XX XXX L C x xi xv xx xxx l c Roman Numerals Cont’d 12 1/2 xiiss 26 xvi 32 xxxii Size of Fractions Numerator top number Denominator bottom number the closer the numerator is to the bottom number the closer to 1 or the bigger it is e.g. 5/6 is greater than 3/6 = 1/2 the larger the denominator with 1 as the numerator the smaller the fraction e.g. 1/100 is smaller than 1/50 Least term 4/6 divide 2 into the top and bottom = 2/3 no other numbers will go into both numerator and denominator Making a common denominator 1/5 + 2/3 (multiply the 2 denominators) (cross multiply the numerators) 3/15 + 10/15 = 13/15 Common denominator for mixed fractions 3 1/2 + 2 3/4 ( multiply denominator by the whole # then add the numerator) 7/2 + 11/4 ( then make a common denominator) = 14/4 + 11/4 = 25/4 = 6 1/4 (to revert to mixed fraction,divide the denominator into the numerator and the difference 2524 is the numerator of fraction)