Percent means "for every 100" or "out of 100". The % symbol is a shorthand way to write a fraction with a denominator of `100`.
`50%` (read as "fifty percent") is equal to `50/100`, `0.50`, or `50:100`.
Percentages are used to express a proportionate part of a total.
For example, if `50%` of the total number of chickens in a coop are roosters, that means that 50 out of every 100 chickens are male. If there are `2000` chickens, then `1000` of them are male. We can calculate this by multiplying the total number of chickens (`1000`) by the percentage (`50`) and then dividing the result by `100`, like this: `50x2000/100 = 1000`.
Another example, if you have `920` chickens and `368` are female - what percentage are female? First compute the ratio `368/920 = 0.4`, and then multiply by `100` to obtain `40%`.
The percent value can also be found by multiplying first, so in this example the `328` would be multiplied by `100` to give `328,000`, and this result would be divided by `920` to give `40%`.
If your answer is negative then this is a percentage decrease.
When shopping, you often see something on sale, advertised at 20% (or some other value) percent off? How much is it going to cost? Armed with your knowledge of percentages you can easily calculate how much you will save. You first multiply the the price (say `$75`) by the percentage deduction (`20%`, and then divide by `100`. Like this: `75x20/100 = 15`.