School mathematics. How to find a percentage of the number

The word "percent" in Greek means a hundredth part of the number. In mathematics, and indeed throughout the world, it is customary to consider the absolute as 100%. Based on this principle, all computational rules are constructed.

There are several variants of tasks related to the purpose of calculating the percentage of the number. Each such task has its own individual principle of solution.

Find the percentage of the number

In the condition of the problem a certain numerical value is given and it is required to find its percentage. For example, we have the number 47 and we need to calculate it 25%.

Decision:For the solution, we take the original number as 100%. After that, this percentage is converted to decimal and we get that 25% = 0.25. Multiply 47 by the percentage expressed in the fraction, and we obtain the desired number 47 * 0.25 = 11.75.

Answer: 11.75 is 25% of the number 47.

Find the number by percentage

The next type of tasks related toThe question of how to find a percentage of a number is the calculation of the value by the available percentage. It is given that 57 is 45% of some number. It is required to find this number.

Decision:To solve such a problem, it is necessary to divide the existing number by the percentage that it makes up from the whole. So, we get that 57 / 0,45 = 126,67. To better understand this action, it will be superfluous to disassemble the entire process in detail. 57 is 45%, i.e. To find the value of one percent, you need to divide the number by the number of percentages. It turns out that 1% of the whole number is 1.2667. Further, to find the whole, we multiply the obtained value by 100.

Answer: The number, 45% of which is 57, is 126.67.

Find how many percent one number is from another

It is a little more difficult to imagine tasks in whichit is necessary to find the percentage value that one number is from the other. How to find a percentage of the number in this case? The answer is very simple. Consider it in a small example. We have two numbers: suppose it is 45 and 58. To find out how many percent is 45 from 58, it is necessary to multiply it by 100 and divide by 58. We get that 45 is 77.6% of 58.

Often you can see situations where people do notunderstand how the price of the product will change if it increases by 15%. People forget elementary school mathematics and for this reason are wondering how to find a percentage of the number.

Knowledge of interest in the sphere ofexchange communications and operations. When making deposits in a bank account, we also deal with interest. There is often a principle of floating interest or capitalization, which complicates the principle of calculating the final total.

As we see, with a small repetition it is possible witheasy to remember, or re-learn how to find a percentage of the number, and indeed how to work with such a mathematical and financial unit. This knowledge will not only broaden the overall human horizon, but also help you more confidently navigate in situations with changes in prices, exchange rates, bank interest, rate of return, and other very important processes. Of course, at first glance it seems that the ability to calculate in the mind can save only a few seconds, but the winning minute from making one decision can result in several days of release a year.