Chapter 50: Measurement Systems, Basic Mathematics, and Dosage Calculations

Which system is the primary system of measurement in medicine, based on multiples of 10?

a. Metric

b. Apothecary

c. Imperial

d. Household

a. Metric

Patients at home typically use household measurements such as:

a. tablespoon and teaspoon

b. gram and milligram

c. liter and milliliter

d. meter and millimeter

a. tablespoon and teaspoon

The top number of a fraction is called:

a. percentage.

b. eliminator.

c. numerator.

d. denominator.

c. numerator.

Which calculation method uses the following:

Dosage on hand: Amount on hand = Dosage desired: x (Amount desired)

a. Apothecary method

b. Algebraic method

c. Ratio and proportion method

d. Basic formula method

c. Ratio and proportion method

Which system of measurement is most commonly used in health care?

a. Standard

b. Metric

c. Apothecary

d. Household

b. Metric

Drop, cup, and pint are measurements in which system?

a. Metric

b. Apothecary

c. Standard

d. Household

d. Household

The prefix centi- means:

a. 1/100 of a unit.

b. 1/10 of a unit.

c. 100 units.

d. 10 units.

a. 1/100 of a unit.

In the basic formula method, the prescribed amount would be inserted into what place in the formula?

a. Dose

b. Needed

c. Available

d. Vehicle

b. Needed

What are the three steps used in finding the correct amount of medication in the ratio and proportion method?

a. Convert, calculate, confirm

b. Convert, construct, calculate

c. Construct, calculate, convert

d. Calculate, convert, confirm

b. Convert, construct, calculate

What is the conversion factor for converting pounds into kilograms?

a. lb = 1 kg

b. 1 kg = 2.2 lb

c. 1 kg = 2 lb

d. 2 lb = 1 kg

b. 1 kg = 2.2 lb

A ratio expresses the relationship between how many components?

a. Four

b. Two

c. Three

d. Five

b. Two

You have acetaminophen elixir, which is labeled 325 mg/5 mL, on hand. The provider ordered 650 mg by mouth (PO). How many milliliters would you administer?

a. 5 mL

b. 10 mL

c. 15 mL

d. 20 mL

650/325 x 5

2x5= 10

b. 10 mL

Lasix is available in 40 mg scored tablets. The provider ordered the patient to take 60 mg by mouth (PO) every morning. How many tablets would the patient take?

a. 1 ½ tablets

b. 2 tablets

c. 1 tablet

d. 2 ½ tablets

60/40 x 1

1.5 x 1= 1 1/2

a. 1 ½ tablets

A patient has presented to the clinic with a poison ivy rash and the provider has ordered you to give them Benadryl elixir 25 mg by mouth (PO). You have 12.5 mg per 5 mL on hand. How many mL will you administer to the patient?

a. 10 mL

b. 12.5 mL

c. 5 mL

d. 25 mL

25/12.5 x 5

2 x 5= 10

a. 10 mL

Medications can be described in ______ measurements.

metric

The metric system has three basic units: gram, liter, and meter. What does a liter measure?

a. Volume (liquid)

b. Mass (weight)

c. Solids

d. Length (size)

a. Volume (liquid)

A ratio expresses a ______ between two components and is an alternate way to express a fraction.

relationship

When adding or subtracting fractions, the ______ must be the same before adding or subtracting.

denominator

A kilometer has a value of how many meters?

a. 100

b. 1000

c. 10

d. 500

b. 1000

A ______ expresses a value that is part of 100.

percentage

What is the answer to the following equation?

213 × 6

a. 3098

b. 2145

c. 4999

d. 1278

d. 1278

½, ⅚, or 12/100 are examples of:

a. improper fractions.

b. mixed fractions.

c. fractions.

d. denominators.

c. fractions.

The values within a proportion are called means and extremes. The extremes are which of the following?

a. Outer number and one to the left of the equal sign

b. Numbers directly to the left and right of the equals

c. Two outer numbers

d. One outer number and one to the right of the equal sign

c. Two outer numbers

Medication dosages are ordered by _____ of measurements.

units

The basic formula method is which of the following?

a. A/V ×N=Dose

b. A/N ×V=Dose

c. V/N ×A=Dose

d. N/A ×V=Dose

d. N/A ×V=Dose

How many tablets would you give in the following example?

Order: Give baby aspirin 162 mg; Supply: Baby aspirin 81 mg tablet

a. 1

b. 2

c. 3

d. 4

162/81 x 1

2x1= 2

b. 2

When the order of a medication is 200mg and the medication is available in 50mg tablets, the dose for this patient is:

a. 3 tablets.

b. 4 tablets.

c. 5 tablets.

d. 2 tablets.

200/50 x 1

4 x 1= 4

b. 4 tablets.

If you have an order for 1000 mg Tylenol elixir and the supply is Tylenol elixir 500 mg per 15 mL, what would the dosage be?

a. 20 mL

b. 10 mL

c. 30 mL

d. 15 mL

1000/500 x 15

2 x 15 = 30

c. 30 mL

Sometimes a medication is ordered in one unit of measurement but is supplied in another. One way to convert between units of measurement is to set up a ______ of two ratios.

proportion

A person who weighs 125 pounds weighs approximately _____ kilograms.

a. 27.5

b. 250

c. 275

d. 56.82

d. 56.82

Some medications are ordered based on the patient's weight, which usually requires a conversion from pounds to:

a. dekagrams.

b. milligrams.

c. kilograms.

d. micrograms.

c. kilograms.