Percentage is a hundredth of a number taken as an integer. They are used to indicate the relationship of a part to a whole and to compare quantities.

## Interest history

Long before the advent of the decimal system, the ancient Romans knew how to operate with fractions that are multiples of a hundred. Thus, a tax in the amount of a hundredth of the price of goods sold at auction was levied under Gaius Julius Caesar. In medieval Europe, calculations with a denominator of 100 were already commonplace. At the end of the 15th century - the beginning of the 16th century, such calculations were used everywhere. Documents have been preserved confirming the methods for determining profits, losses, interest rates, etc. In the 17th century, the presentation of interest rates in hundredths became the standard.

In Russia, interest calculations began to be used during the reign of Peter I (late 17th - early 18th centuries). But some historians believe that this happened a hundred years earlier - in the Time of Troubles (1598-1613) they minted kopecks, constituting a hundredth of the ruble.

## Interesting facts

- The length of the femur is about 27.5% of the height, it is the longest bone in the human body. Muscle weight in men is on average 40% of body weight, in women - 30%.
- All living organisms on the planet are made of water. The water content in the human body changes with age, in infants it reaches 86%, in the elderly the humidity drops to 50%. Animals and fish contain 75% water, apples 85%, tomatoes 90%, cucumbers 95%. Jellyfish are 99% water, but do not dissolve in it.
- A person experiences intense thirst at a loss of 2% of water from body weight. With a loss of 10%, hallucinations begin. 20% dehydration is usually fatal.
- 60% of the world's lakes are located in Canada and occupy 9% of the country's territory.
- 99% of Libya is desert, it is the driest country.
- In Latin, per centum means "hundred". The % sign is an abbreviation for the Italian term per cento.

Not only bankers, mathematicians and businessmen cannot do without the ability to calculate interest. The need to calculate the percentage periodically arises when preparing dishes in cooking, analyzing the activities of enterprises, summing up the results of voting during elections, and in many other cases. With the interest calculator, you will not make a mistake in the calculations.