To understand the % sign, ask yourself the following four questions:
(1)
What does the % sign mean?
. . .
A % is used to
compare
a
number
(any number)
to 100
using division.
Under normal circumstances, all numbers are compared to the number 1 using division.
For example, the number 3 is only a 3 when it is compared to the number 1 using division. It is three times as big as the number 1.
However, a % does not use the number 1 for comparison purposes.
A % is used to compare a number (any number) to 100 using division.
Continuing on with the number 3 as an example, the result would be: (Note that the quotient must still equal 3. The number 300 is three times as big as 100.)
The final percentage is:
3 = 300%
. . .
Any number can be converted to a %. You can complete a short calculation similar to the example shown above, or . . .
. . . Just move the decimal point to the right by two places.
(2)
Where is a % math symbol used?
A % math symbol is only used to represent a proportion.
A percent tells you that you are dealing with a
ratio.
Although any number can be converted into a %, percents are only used to represent ratios.
What is the point of converting a ratio to a %?
Why not just skip the % and use the original number?
Is there any advantage to saying 5.6% instead of .056?
Read on . . .
(3)
How is a % math symbol used?
There are thousands and thousands of applications where the concept of a percent is used every day.
Here are some common examples:
. . .
Sales Tax . . . . . . If you pay sales tax, the tax will be stated as a %. If the sales tax is 8%, this means that you will pay the government a tax of 8 dollars for every 100 dollars you spend.
. . .
Bank Interest . . . . . . If you deposit money in a bank, the interest the bank will pay on your account will be stated as a %. If the interest rate is 5% (simple annual interest), this means that the bank will pay you 5 dollars for every 100 you leave in your account for one year.
. . .
Credit Card Interest . . . . . . If you use a credit card, the interest you pay on the outstanding balance you owe will be stated as a %. If the interest rate is 20% (simple annual interest), this means that you pay the credit card company an extra 20 dollars per year for every 100 dollars of unpaid debt.
. . .
Test Grades in School . . . . . . Test grades in school are often stated as a %. If a student has a test average of 81%, this means that for every 100 questions the student answers on his or her tests, 81 questions are answered correctly.
. . .
Slope of a railroad track . . . . . . Slope is often stated as a %. If a slope of a railroad track is a 5% grade, this means that for every 100 feet of horizontal distance the tracks drop 5 feet in elevation.
. . .
Survey (Poll) . . . . . . Survey results are often stated as a %. If a survey found that 75% of restaurant patrons preferred a certain type of food, this means that for every 100 people, 75 people prefer that type of food.
(4)
What math symbols can be mistaken for a % sign ?
. . .
Per mille . . . . . . The Per mille symbol is not equivalent to a Percent symbol.
1 % means 1 part in 100.
1
means 1 part in 1000.
. . .
Basis point . . . . . . The Basis Point symbol is not equivalent to a Percent symbol.
1 % means 1 part in 100.
1
means 1 part in 10000.
