Ratios, Proportions, Decimals & Percents

Question 1

Dimensional Analysis

Answer 1

Calculation by Cancellation

a problem solving method that uses the fact that any number or expression can be multiplied by one of its units without changing its value

ex. How many eggs are in 3 dozen?

eggs are a unit of a dozen

12 eggs = 1 dozen

Question 2

ratio

Answer 2

numerical relationship between two numbers showing the nuber of times one unit is contained within another

ex. 12 eggs/1 dozen

$2.50/1 gal

when ratios are used with numbers of the same units, it expresses parts of a whole

ex. 4 oz milk/16 oz gravy (read as 4 oz of milk in 16oz total of gravy)

Question 3

1:1000

Answer 3

commonly understood pharmaceutical ration meaning

1 g/1000 mL

the following is also true in relation to gram/liter

1 mg/1mL = 1 g/1000mL

Question 4

proportion

Answer 4

mathematical equation that expresses an equality relationship between two ratios

ex. A/B = C/D -or- A is to B as C is to D
- then-

B/A = D/C is also true (inverse)

-so-

the value of a proportion lies in the fact that cross multiplying leads to an equality

ex. A x D = B x C
- and-

if 3 of the values are known, you can solve for the 4th.

Question 5

decimals

Answer 5

ex. = 0.25

commonly used in pharmacy and are frequently used with the metric system to express ratios as the metric system is based on values of 10 – as is the decimal system

Question 6

percent

Answer 6

• comes from the Latin meaning “in one hundred”
• alternate expressions for fractions

Question 7

dimension

Answer 7

composed of a number and a unit