Introductory Pharmacology - Fractions

Ann MacLeod, RN, BScN, MPH

Objectives

Convert Roman Numerals to ArabicConvert Arabic to Roman NumeralsCompare the size of fractionsAdd and subtract fractionsDivide and Multiply fractionsReduce fractions to the lowest terms

Roman Numerals1/2 ss1 I, id2 II ii3 III iii4 IV iv5 Vv6 VI vi7 VII vii8 VIII viii9 IX ix

10 X x11 XI xi15 XV xv20 XX xx30 XXX xxx50 L l100 C c

Roman Numerals Cont’d

12 1/2 xiiss

26 xvi

32 xxxii

Size of Fractions

Numerator top numberDenominator bottom numberthe closer the numerator is to the bottom

number the closer to 1 or the bigger it ise.g. 5/6 is greater than 3/6 = 1/2the larger the denominator with 1 as the

numerator the smaller the fractione.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 25-24 is the numerator of fraction)