Calculations I Flashcards
What are the different ways drugs can be measured?
- Weight (grams, milligrams, micrograms, nanograms)
- Liquid volumes (liters, milliliters)
- Percentage strengths
- Concentrations of a given amount of drug in a given volume of liquid
- Concentrations using milliequivalents per liter
What is the conversion of tsp to mL?
1 tsp = 5 mL
What is the conversion from tbsp to mL?
1 tbsp = 15 mL
What is the conversion from fl oz to mL?
1 fl oz = 30 mL (approx) or 29.57 (actual)
What is the conversion from cup to oz and mL?
1 cup = 8 oz = 240 mL (approx) or 236.56 mL (actual)
What is the conversion of pint to oz and mL?
1 pint = 16 oz = 480 mL (approx) or 473 mL (actual)
What is the conversion from quart to mL?
1 quart = 960 mL (approx) or 946 mL (actual)
What is the conversion from gallon to mL?
1 gallon = 3840 mL (approx) or 3785 mL (actual)
What is the conversion from kg to pounds?
1 kg = 2.2 pounds
What is the conversion from oz to g?
1 oz = 28.4 g
What is the conversion from pound to g?
1 pound = 454 g
What is the conversion from grain to mg?
1 grain = 65 mg (approx) or 64.8 mg (actual)
What are the steps to round on the exam?
1) Underline the number to the right of what is being rounded
2) Look at the number that is underlined and apply one of these rules:
- If underlined number is 5-9, round up
- If underline number is 0-4, round down
When should you round on calculations?
Never round until the last step in the calculation
What are proportions?
Proportions are two fractions (ratios) that are set equal to each other. One variable is unknown and labeled “X”
How do you set up proportions?
When setting up proportions, make sure that the units for the numerators match to each other and the units for the denominators match to each other or make sure the items in the left fraction match and the items in the right fraction match
What is dimensional analysis?
Dimensional analysis allows multiple proportion calculations to be completed quickly
How is dimensional analysis set up?
Diagonal units that are the same can be crossed out (“canceled out”), leaving the desired units. The numbers can be plugged into the calculator exactly as written
What is a ratio?
A ratio is a comparison between two numbers. Ratios can be used to describe how ingredients should be mixed
How do you convert a decimal to a percentage?
To convert a decimal to a percentage, multiply the decimal by 100
How do you convert a percentage to a decimal?
To convert a percentage to a decimal, divide the percentage by 100