## Percent. Percentages.

### Percent

- Percent is one hundredth of a given amount, is an amount calculated with reference to a hundred, hundredth, 1: 100 = 1/100, ie. a fraction with numerator equal to 1 and denominator to one hundred.
- The word comes from the Latin "per Centum", meaning "by the hundred". The latin word "Centum" means "100", for example a century is 100 years. So, "percent" means "per 100".
- Percent means 1/100, two percent means 2/100, three percent means 3/100, and so on.
- Although a fraction, the percent occurs in writing without the denominator (100), but only with the numerator, followed by the sign%: 1 percent = 1%, two percent = 2%, three percent = 3%, and so on.

### Percentage

- Percentage is the "result of multiplying a quantity by a certain percent".
- So 10 percent (10:100 = 10/100 = 10%) out of 50 apples is 5 apples (10% of 50 = 10/100 * 50 = 500/100 = 5) - the 5 apples is the percentage.

### When do we say percent or percentage?

- It is correct to say: a result of 7 percent, or 7%, or a percentage of 7%.
- It is incorrect to say: one percent of 7% (one percent is exactly 1% of something).

### Percentages trasformed into decimal numbers:

- One percent, 1%, means 1 per 100, 1% = 1/100 = 0.01.
- Fifty percent, 50%, means 50 per 100, 50% = 50/100 = 1/2 (half) = 0.5.
- One percent of 70 is: 1% of 70 = 1/100 * 70 = 7/10 = 0.7
- Fifty percent of 70 is: 50% of 70 = 50/100 * 70 = 1/2 * 70 = 35.