1. Chapter 5
Medical Math

2. Importance of Math Frequently used in health care
Requires 100% accuracy
Errors can have dire consequences

3. Math Anxiety Common problem Impedes performance Can be overcome
False beliefs versus reality

4. Question True or False:
If a person currently has problems with math, it can be assumed that it will always be a problem.

5. Answer
False
Math anxiety
Learned behavior
Can be overcome

6. Basic Calculations
Whole numbers
Add
Subtract
Multiply
Divide

7. Decimals Expressed in units of ten Placement values
Zero used before decimal point if number begins to right of decimal point

8. Decimal Placement Values

9. Working with Decimals Placement of decimal Add Subtract Multiply
Divide

10. Fractions
Represents part of a whole
Numerator
Denominator

11. Fraction – Comparison of Parts

12. Working with Fractions
Add
Subtract
Multiply
Divide
Improper fractions
Reducing fractions

13. Percentages Expresses whole or part of a whole
Whole expressed as 100% (percent)
Convert to decimal
Then perform calculation

14. Ratios Show relationships between numbers or like values
Compare presence of one value to another
Frequently used to express strength of solution

15. Converting Decimals, Fractions, and Percentages
Decimal to fraction
Decimal to percentage
Fraction to decimal
Fraction to percentage

16. Converting Decimals, Fractions, and Percentages
Percentage to decimal
Percentage to fraction
Percentage to ratio
Ratio to percentage

17. Question
True or False:
¾, 75%, and 0.75 are all equivalent.

18. Answer True ¾ Fraction If converted to percentage = 75%
If converted to decimal = 0.75

19. Rounding Numbers
What does it mean?
Round up
Round down

20. Question
What is rounded to the nearest tenth? 2
2.3
2.35

21. Answer B. 2.3 2.346 rounded to nearest tenth = 2.3
2.346 rounded to nearest whole number = 2
2.346 rounded to nearest hundredth = 2.35

22. Solving with Proportions
Statement of equality between two ratios
Used for converting from one unit to another
Steps for solving problems

23. Estimating Anticipate results Determine if answer is reasonable
Calculate approximate answer
Helps prevent errors

24. Question
If the order is to give 2 grams of a medication and you have 1,000 milligram tablets, how many tablets would you give?
½ tablet
2 tablets
4 tablets

25. Answer B. 2 tablets 1 gram = 1,000 milligrams
2 grams = 2,000 milligrams or 2 tablets
½ tablet = 500 milligrams
0.5 grams (too little)
4 tablets = 4,000 milligrams
4 grams (too much)

26. Military Time 24-hour clock No a.m. or p.m. Avoids errors
12th hour = noon
24th hour = midnight

27. Question True or False:
The military time of 1600 is the same as 6 p.m. traditional time.

28. Answer
False
1600 = 4 p.m.
6 p.m. would be 1800 military time

29. Military Clock

30. Roman Numerals Arabic versus Roman numerals
All numbers from seven key numerals
I, V, X, L, C, D, and M

31. Roman Numerals Rules
If smaller numeral is in front of larger numeral, it is subtracted
If smaller numeral is after larger numeral, it is added
If same numeral is repeated, they are added
Limit to three the number of times numeral is placed next to itself

32. Question
How would 43 be written in Roman numerals?
XLIII
XXXXIII
XXXI

33. Answer A. XLIII XLIII = 43 XXXXIII incorrect XXXI = 31
Same numeral cannot be placed next to itself more than three times
XXXI = 31

34. Angles Comparison to reference plane Using angles in health care
Measured in units
Degrees

35. Angles

36. Systems of Measurement
Three systems
Distance
Length
Capacity
Volume
Mass
Weight

37. Systems of Measurement
Nomenclature
Method of naming
Need to convert between systems

38. Household System Used in U.S. Nomenclature for distance/length
Nomenclature for capacity/volume
Nomenclature for mass/weight
Common equivalents
How to convert

39. Question
Which of the following is a capacity/volume unit in the household system?
Inch
Pound
Ounce

40. Answer C. Ounce Inch = measurement of distance/length
Also measurement of mass/weight
Inch = measurement of distance/length
Pound = measurement of mass/weight

41. Metric System Used in Europe More accurate Easier to use
Based on unit of ten
Convert units by moving decimal
Common prefixes

42. Metric System Nomenclature for distance/length
Nomenclature for capacity/volume
Nomenclature for mass/weight

43. Question
How many centimeters are there in one meter? 10
100
1000

44. Answer B. 100 Meter Base unit for distance/length in metric system
Centi = 1/100
1 meter = 100 centimeters

45. Apothecary System Oldest and least used
Nomenclature for capacity/volume
Nomenclature for mass/weight
Common equivalents
How to convert
Roman numerals and abbreviation for half

46. Converting Systems
Why converting between systems is needed in health care
Common equivalencies between systems
Equivalencies frequently not exact
Steps to convert

47. Question
A patient reports drinking 8 ounces (oz) of water. What is this in milliliters (mL)?
80 mL
120 mL
240 mL

48. Answer
C. 240 mL
1 oz = 30 mL
8 oz = 240 mL

49. Medication Safety
Characters that cause over 50% of error misidentifications:
l/1
O/0
Z/2
1/7

50. Temperature Conversion
Fahrenheit (F) used in U.S.
Celsius (C) used in Europe
Boiling point and freezing point comparisons
Converting between Celsius and Fahrenheit readings

51. Temperature Scales

52. Question
True or False:
37 degrees C is a normal reading.

53. Answer
True
37 degrees C = 98.6 degrees F
Normal reading