How do you calculate percentages?

How to find a percentage of the amount in the General case?

Before you calculate the percentage of the amount you need to calculate the size of the per cent. For this purpose it is enough to take the total amount and divide it by 100, the result will be just 1%.

Then there are two options:

If you want to know how many percent is another sum of the original, you simply split it into size 1% received earlier.
If the same amount is needed, that is, say, 27.5% of the original size, you need 1% multiplied by the desired percentage.

How to calculate percentage of amount using the aspect ratio?

But you can do otherwise. Using knowledge about the method of proportions, which are part of school mathematics. It will look like this.

Let we have a — basic amount equal to 100%, and-the amount, the ratio and percentage, we need to know. Write a proportion:

A = 100

B = X

(X in this case is the number per cent).

According to the rules for calculating the proportions we get the following formula:

X = 100 */a

If you want to know how many will be amount with the known number of percentage and, the formula will look differently:

In = 100 * x/a

Now we substitute in the formula known in number — and you can make a calculation.

Finally, you can use a simpler way. For this purpose it is enough to remember that 1% as a decimal is 0.01. Accordingly, 20% is 0.2; 48%-0.48; 37.5% is 0.375 etc. Enough to multiply the original amount on the corresponding number — and the result would mean the amount of interest.

In addition, sometimes you can use simple fractions. For example, 10% is 0.1, i.e. 1/10 therefore know how many will make up 10%, simply: you just need to divide the original amount to 10.

Other examples of such ratios are:

12.5%-1/8, that is, you want to divide into 8;
20%-1/5, i.e. the need to divide by 5;
25%-1/4, that is, divide by 4;
50% is 1/2, there is a need to split in half;
75% is 3/4, i.e. the need to divide by 4 and multiply by 3.

It is true that not all fractions are useful for calculating interest. For example, 1/3 is close in size to 33%, but is not exactly: 1/3 is 33, (3)% (i.e. the fraction with endless triplets after the comma).

How to deduct a percentage of the amount without the aid of a calculator

If you want to deduct from the amount of known unknown number some percentage, you can use the following methods:

Calculate an unknown number using one of the above methods, and then subtract it from the original.
Immediately calculate the remaining amount. To do this from 100% remove the percentage that you want to subtract, and result from translate per cent in the number of any of the above methods.

The second example is more convenient, therefore, to illustrate it. Let’s say, you have to know how many will remain, if take 16% 4779. The calculation would be:

Deduct from 100 (percent) 16. Get 84.
Consider how many will reach 84% of 4779. Get 4014.36.

How to calculate the sum of (subtract) with a percentage calculator in hand

All the above calculations easier to do using the calculator. It can be in the form of a stand-alone device or as a special program on a computer, Smartphone or mobile phone (even the oldest of currently used devices usually have this feature).

How to take away from the amount of the percentage using online calculator

Finally, online enough sites where implemented the function online percentage calculator. In this case, you don’t even need to know how to calculate percentage of amount: all user operations are confined to Windows right digits (or movement of the sliders to get them), then the result is immediately displayed on the screen.

This feature is especially useful to those who counted not just an abstract percentage, but the size of the tax deduction or the amount of the registration fee. The fact of the matter is that in this case the calculation more difficult: you want to find the interest, but also add to it a permanent part of the sum. Online calculator allows you to avoid such incremental computing. The main thing is to choose the site that has the data that correspond to the current law.