Several ways to calculate the percentage of a number (and tasks of a similar type)

Calculating the percentage of the number is one of the fundamental topics that all take place in school in math lessons. But this does not mean that everyone learns it with ease. In fact, the topic is simple, the main thing is to know the proven methods of calculating the whole by parts and percentages of the whole.

1% is the one-hundredth part of the whole, so knowing this value, you can easily calculate the value of the part. For example, 15% of the number 60 can be calculated as follows: take 60 per 100 percent. Then 1% is 60/100 - 0.6. 15%, thus, will be - 0,6 * 15 = 9. This is the first way to calculate the percentage of the number.

The second way is to make up the proportion. 15 refers to 100, as X refers to 60, i.e. 15/100 = x / 60. You can solve the composition in two ways:

1. Convert it to the expression x = 15 * 60/100. And again it turns out: x = 9.
2. To make another transformation, into 2 actions: 100x = 15 * 60, that is, the numbers in the proportions are multiplied crosswise. From this expression we get the following: 100x = 900. Consequently, x = 9.

If you need to find out what percentage of the number is another number, the formula is also very simple. Take, for example, the numbers 70 and 13. Let 70 be 100%, and 13 - x. Then 13/70 = x / 100. Solve this proportion can be already familiar ways.

70x = 13 * 100; 70x = 1300; If you round to the second decimal place, it turns out that x = 18.57%.

If you know the percentage of a certain number and you need to find this number, then this task can be completely solved.

For example, 16% is 32. What is an integer? Again, make up the proportion: 16% refers to 100%, as well as 32 to x. 16/100 = 32 / x; 16x = 3200; X = 3200/16 = 200.

If the condition of the problem is such that the number A is a certain percentage of the number B, which must be calculated, then another very simple formula is applied. A / B * 100% - this is the answer. For example, you need to find out how many percent the number 87 is from the number 329.

Calculating the result by the formula, we obtain 87/329 * 100% = 26.44%. If the formula is forgotten at the right time, the proportions will come to the aid again: 87 refers to 329, as x refers to 100%, that is 87/329 = x / 100. Having transformed this proportion, we obtain 329x = 87 * 100; 329x = 8700; X = 8700/329 = 26.44%.

Well, the simplest proportions are almost always in everyone's ear and head: one fifth is 20%, one tenth is 10%, half and a quarter are 50% and 25%, respectively. For someone, it's more convenient and clearer to think in parts, and it's easier for someone to operate with interest. There is not much difference between one second and 50%.

With a calculator and it will be easy and simple, because there even has a special button that allows you to calculate the interest.

Of course, all these tasks are simply the consolidation of the theory. But calculate the percentage of the number may be needed in life. On sales, to find out if a 30% discount is worth grabbing for a thing, or it amounts to a paltry amount. You can find out what the price was before the discount, as well as cross-check the sellers - after all, they often use the inattention of customers and point out the price tags are extremely attractive figures.

Calculate the percentage of the number may be needed and when calculating taxes, of course, for those who track such things. Well, of course, with the calculation of interest constantly facing accountants, economists, stock brokers and analysts. In fact, even housewives are constantly dealing with interest, without even noticing it.

In a word, the topic is not difficult, although it seems at first glance to be very difficult. However, when understanding comes, the tasks relating to the calculation of percentages of the number and the whole in part will appear as seeds. You just need to fill your hand and move your brains a little.