Nursing students need basic math skills to safely administer medications. This document provides a refresher on Roman numerals, fractions, decimals, and rounding rules. Roman numerals follow the general rule of placing larger numerals to the left and adding, with the exception being smaller numerals preceding larger ones are subtracted. Fractions represent the division of a whole into parts with the numerator and denominator. Decimals place values decrease moving right of the decimal point. Rounding rules state to round up if the digit is 5 or greater and down if less than 5, rounding to the nearest hundredth under 1 and tenth above 1 for measurements in mL or cc.

1. Basic Math Refresher

2. Basic Math Refresher
Nursing required competency in mathematical skills in order for you to be able to
administer medications to your patients safely. Use the following basic math
refresher to build the foundation for developing proficiency in the mathematical
skills necessary for nursing.
Roman Numerals
I=1 V=5 X=10 C=100 D=500 M=1000
Roman Numerals - General Rule
The basic form is to place the larger numerals to the left and add other numerals.
Example: XXXIII = 33, which is (XXX = 30) + (III = 3) = 33
Note: If there seems to be several ways of writing a number, use the shorter form.
XXI – 21, which is (XX=20) + (I = 1) = 21, not XVVI (X = 10 + V = 5 + V = 5 + I = 1)

3. Basic Math Refresher
Roman Numerals – Exception
The exception to the basic form is if smaller numerals precedes a larger numeral, the
smaller should be subtracted from the larger.
Example: IX = 9
(I = 1) - (X = 10) = 1 – 10 (really 10 – 1) = 9
Note: only one smaller numeral can precede a larger numeral.
Example: XCV = ((X = 10) – (C = 100)) + (V = 5) = 95 correct, not IXCV (two smaller
numerals preceding the C (100)).
Note: Roman numerals can be written in upper case and lower case.
Examples: IV or iv = 4

4. Basic Math Refresher
Fractions
A fraction is a way of representing division of a 'whole' into 'parts'. It has the
form:
Numerator
Denominator
where the Numerator is the number of parts chosen and the Denominator is
the total number of parts.

5. Basic Math Refresher
FRACTION TYPES
There are 3 different types of fractions:
•Proper Fractions: Numerator < Denominator - Proper fractions
have the numerator smaller than the denominator. Examples
are ½, ⅖, or ⅞.
•Improper Fractions: Numerator > Denominator or Numerator =
Denominator - Improper fractions have the numerator greater or
equal to the denominator. Examples are 5/5 or 7/2.
•Mixed Fractions - Mixed fractions have a whole number plus a
fraction. Examples are 2 and ⅕ or 123 and ⅞.

6. Basic Math Refresher
Converting a fraction into a decimal - examples
1 0.3333 1 ____ 0.25
--- = 4) 1 = 4 ) 1.00
--- = 3 ) 1.0000 4 8
3 9 20
10 20
9 0
10
9
10
9
10 infinite

7. Basic Math Refresher
Decimals
Decimals and the conversion of decimals to fractions and fractions
to decimals is a necessary skill in the nursing profession.
Relative Values of Decimals
Values on the left side of the decimal are increasing in value
100.00 is larger than 10.00
Values on the right side of the decimal are decreasing in value
0.1 is larger than 0.01

8. Basic Math Refresher
Relative Value of Decimals
1234.5678
Thousands
Ten Thousandths
Hundreds
Hundredths
Tens Thousandths
Ones Tenths

9. Basic Math Refresher
Convert a decimal into a fraction - example
.25 = 25 hundredths (5 is in the hundredths position)
= 25
100 (reduce the fraction)
= 1
4

10. Basic Math Refresher
Rounding Rules
ml or cc Tablets
If the answer is < 1cc (or ml) then Tablets, as a rule, can only be
round to the nearest 100th. given whole or broken in half.
Ex: 0.376 = 0.38 cc (or ml)
If the answer is > 1cc (or ml) then Round to the nearest half (0.5)
round to the nearest 10th. Ex: 1.45 = 1.5 tablets 1.2 = 1
Ex: 1.57 = 1.6 cc (or ml) tablet
Round at the end of the problem, when you get to the answer (exception is when
you’re converting pounds to kilograms (kg)) then you should round to the nearest tenth
as soon as you convert, then complete the problem. (2.345 = 2.4)

11. Basic Math Refresher
Rounding Rules
• Rou
Basic Rounding Remember
If the number is ≥ 5 then round up. Round at the end of the problem.
Ex: 1.57 = 1.6 1.45 = 1.5
0.686 = 0.69
If the number is < 5 then round down.
Ex: 0.543 = 0.54
Converting pounds and kilograms
Round to the nearest 10th. The exception to this rule is when you are
Ex: 120 pounds = 54.54 or 54.5 kg converting pounds to kgs. Always convert
and round to the nearest 10th and then
complete the problem.