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)
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
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.
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.
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
Basic Math Refresher Relative Value of Decimals 1234.5678 Thousands Ten Thousandths Hundreds Hundredths Tens Thousandths Ones Tenths
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
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)
Basic Math Refresher Rounding Rules • RouBasic Rounding RememberIf the number is ≥ 5 then round up. Round at the end of the problem.Ex: 1.57 = 1.6 1.45 = 1.50.686 = 0.69If the number is < 5 then round down.Ex: 0.543 = 0.54Converting pounds and kilogramsRound to the nearest 10th. The exception to this rule is when you areEx: 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.