What is a Percentage?

Percentages
A percentage is a ratio expressed in a particular way; It is to compare one quantity to 100.
Calculate a percentage:
To simply express a percentage, just clearly place the problem in a table of proportionality to four numbers, which is 100.
For example:
On 835 visitors of a castle in a day, 144 are foreigners; What is one
percentage p you are looking for.
Number of foreigners 144 p
Total visitors 835 100

Apply a percentage
Apply a percentage p % at an amount, it’s multiply this amount by p and divide
by 100.
Decimal expression of a percentage:
A percentage is therefore primarily a special writing a number which can be
expressed in another way; in particular, we can give a simple decimal entry,
or even a fractional writing.
For example, 50% = 0.5. So to calculate 50% of a quantity, you can multiply that by
0.5.
But 50% = 1/2 (half, half). We can so all as well divide the amount by 2.

Increase, decrease
Increase a number by a percentage calculator, this is add this percentage to 100%
initial. Therefore calculate a percentage greater than 100% of the original amount.
For example add 10%, is calculated (100 + 10), i.e. 110% of the original amount.
To the contrary, to withdraw 10%, it is calculating (100-10), 90% of the original amount.