Mathematics is used in everyday life. Even in simple things, when we say what time it is or when shopping. It has significant importance as a science. Roger Bacon wrote in 1267 that mathematics is the “gateway and key to the sciences.” Mathematics is used in increasingly more social sciences, economics, the industry as well as in companies that require research and planning. Such as the plan made by a company to compare their profit with the other two competitors over a period of three months, and the result was: their company had a profit of $3 million, competitor X – $4.1 million, and competitor Y – $1.7 million. By the end of the next three months, the result was: company X had a profit of $10.1 million, company Y had a profit of $7.8 million, and their company ranked first with $11 million.

As a science, mathematics combines the beauty of numbers with the way they interact generating complex formulas, based on which everything around us functions: appliances, cars, computers, etc. Even though things such as polynomials, trigonometric functions, quadratic equations (here we found a good quadratic formula calculator) or integrals are not much of a use in daily life, there are basic parts of mathematics with wide application and practicability such as percentages, probabilities, directly and inversely proportional numbers that we are going to discuss below.

## Percentages

Percentages are used in almost any field. For example politics, agriculture, commercial affairs, and more. In the category of percentages also fall reports that help in solving daily situations.

**In politics**

In this area, we can frame the presidential elections. Using percentages, we can find out how many people would count their vote, how many people vote abroad, etc.

**In agriculture**

In this area, without the help of mathematics, we could not solve anything.

If a farmer has 400 hectares and wants to plant wheat, corn, oats, and barley, how can he know how many hectares to grow from each if he does not know the numbers and how to calculate?

Likewise, if a drought comes and 50% of the total is lost, the harvest will be twice as small, so from 30% as much as maize, only 15% of it will be harvested and so on. If it is known how much soil is prepared for planting each of these seeds, it must be represented as a percentage to find out what profit will be obtained in the end.

Mathematics blends perfectly with chemistry, which is related to agriculture. For example insecticides, herbicides have a number of acids used in their preparation which we can represent as a percentage.

**In business**

This plan includes all the profits, sales of a store in one day or more days.

If a store slashed the price of an item by 20%, many people would buy that product. On the first day, the store sold 60% of all items, on the following day 30%, and on the last day 10%. Percentages help to figure out the number of items sold per day and the profit. The profit on the second day was twice as low as on the first day, and the profit on the last day was six times lower.

**In the pharmaceutical field**

The medicines have different substances from magnesium, iron, potassium, starch, povidone, croscarmellose to hundreds of types of acids. In their manufacturing process, precision and accuracy of maximum concentration for the dosage of the drug must fit perfectly. These dosages can be written in percentages. For example: 12% povidone, 34% stearic acid and 54% magnesium.

## Probabilities

They are encountered almost always in life. Some of the common areas would be:

- First of all, the
**meteorology**where each forecast is based on probability. It is not known for sure what the weather will be like after a few days because the weather is very unstable and unpredictable. **Sports betting**. Again, it is not known who will win a match. Even if in the middle of the game one team ranks first, until the end the result may be totally different.**Gambling**is the same, but one of the most popular odds is the**lottery**and**dice roll**. In the lottery, it is never known exactly which numbers will be drawn, but the probabilities exist. The probabilities, in this case, can be of several types: the probability of coming out an even number, an odd one, a prime number, the probability of coming out a red, green, blue, white or another color. However, the highest probability is to get the numbers put into play.

## Directly and inversely proportional numbers

About these directly and inversely proportional numbers we can say that they are the most used mathematical applications in life.

Some examples that occur in everyday reality:

- Five taps with the same flow (flow = time unit) fill an Olympic basin in 15 hours, so the number of taps is inversely proportional to the number of hours spent to fill the basin. Fewer taps means more hours to fill the basin; while, as the number of taps increases, the number of hours decreases.
- A mother wants to share sweets with her two sons and thinks about dividing the number of sweets in proportion to the age of the children, which means that the youngest child will receive more sweets and the older one will receive fewer. This is another example of inverse proportionality.
- A grandmother made apple juice. If she puts in bottles of 900ml would fill 18 bottles, but she has only 450ml bottles. In such a case she will need more bottles. So, the number of bottles is inversely proportional to the number of milliliters.
- Two brothers start a business. One invests $2000 and the other $8000. The revenue generated by the business will be divided directly proportional to the amount of money invested, so the first brother will earn 4 times less than the second. An example of direct proportionality.
- In addition to being a science, mathematics combines with chemistry and geography, and also with physics. It is known that the distance is equal to the speed multiplied by time. All these terms are sizes. Thus, the distance will be directly proportional to the time, and the speed will be inversely proportional to the time.

Mathematics is and will remain in our lives as long as we live. It will always help us, in any field she will need it!