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)