3 of the total amount. Percent percent calculator
Example 1
You go to the supermarket and see the promotion on. Its usual price is 458 rubles, now there is a 7% discount. But you have a store card, and on it a pack will cost 417 rubles.
To understand which option is more profitable, you need to convert 7% to rubles.
Divide 458 by 100. To do this, simply shift the comma separating the integer part of the number from the fractional one by two positions to the left. 1% is 4.58 rubles.
Multiply 4.58 by 7, and you get 32.06 rubles.
Now it remains to subtract 32.06 rubles from the usual price. On the stock coffee will cost 425.94 rubles. So, it’s more profitable to buy it on the map.
Example 2
You see that the game on Steam costs 1,000 rubles, although it used to be sold for 1,500 rubles. You are wondering how much the discount was.
Divide 1,500 by 100. Moving the comma to two positions to the left, you get 15. This is 1% of the old price.
Now divide the new price by 1%. 1,000 / 15 \u003d 66.6666%.
100% - 66.6666% \u003d 33.3333%. Such a discount was provided by the store.
2. How to calculate the percentage by dividing the number by 10
First you find the size of 10%, and then divide or multiply it to get the right amount of interest.
Example
Let's say you put 530 thousand rubles for 12 months. The interest rate is 5%, capitalization is not provided. You want to know how much money you will take in a year.
First of all, you need to calculate 10% of the amount. Divide it by 10 by moving the comma to the left by one character. You will get 53 thousand.
To find out how much is 5%, divide the result by 2. This is 26.5 thousand.
If in the example we were talking about 30%, you would need to multiply 53 by 3. To calculate 25%, you would have to multiply 53 by 2 and add 26.5.
In any case, using such large numbers is quite simple.
3. How to calculate interest, making a proportion
Making proportions is one of the most useful skills that you have been taught to. With it, you can calculate any percentage. The proportion looks like this:
amount of 100%: 100% \u003d part of the amount: percentage.
Or you can write it like this: a: b \u003d c: d.
Usually the proportion reads as “a refers to b in the same way as c refers to d”. The product of the extreme members of the proportion is equal to the product of its middle members. To find out an unknown number from this equality, one needs to solve the simplest equation.
Example 1
For an example of calculations we use the recipe. You want to cook it and bought a suitable bar of chocolate weighing 90 g, but could not resist and bit off a piece or two. Now you have only 70 g of chocolate, and you need to find out how much butter to put instead of 200 g.
First, we calculate the percentage of remaining chocolate.
90 g: 100% \u003d 70 g: X, where X is the mass of the remaining chocolate.
X \u003d 70 × 100/90 \u003d 77.7%.
Now we make a proportion to find out how much oil we need:
200 g: 100% \u003d X: 77.7%, where X is the right amount of oil.
X \u003d 77.7 × 200/100 \u003d 155.4.
Therefore, approximately 155 g of butter should be put in the dough.
Example 2
The proportion is also suitable for calculating the profitability of discounts. For example, you see a blouse for 1,499 rubles with a 13% discount.
First, find out how much a blouse costs as a percentage. To do this, subtract 13 from 100 and get 87%.
Make a proportion: 1 499: 100 \u003d X: 87.
X \u003d 87 × 1,499 / 100.
Pay 1 304.13 rubles and wear a blouse with pleasure.
4. How to calculate interest using ratios
In some cases, you can use simple fractions. For example, 10% is 1/10 of the number. And to find out how much it will be in numbers, it is enough to divide the whole by 10.
- 20% - 1/5, that is, you need to divide the number by 5;
- 25% - 1/4;
- 50% - 1/2;
- 12,5% - 1/8;
- 75% is 3/4. So, you have to divide the number by 4 and multiply by 3.
Example
You found pants for 2,300 rubles with a 25% discount, but you only have 2,000 rubles in your wallet. To find out if there is enough money for a new thing, do a series of simple calculations:
100% - 25% \u003d 75% - the cost of trousers as a percentage of the original price after applying the discount.
2 400/4 × 3 \u003d 1 800. That is how many rubles are pants.
5. How to calculate interest using a calculator
If life isn’t nice without a calculator, all the calculations can be done with it. And you can do even easier.
- To calculate the percentage of the amount, enter a number equal to 100%, a multiplication sign, then the desired percentage and a% sign. For an example with coffee, the calculations will look like this: 458 × 7%.
- To find out the amount minus interest, enter a number equal to 100%, minus, percentage size and sign%: 458 - 7%.
- Similarly, you can add, as in the example with a deposit: 530,000 + 5%.
6. How to calculate interest using online services
The site contains various calculators that calculate not only interest. There are services for lenders, investors, entrepreneurs and all those who do not like to count in the mind.
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The simplest and most obvious method is to compose a proportion. On its basis, all further calculations take place. It looks like this:
- 45 is a known number equal to 100%.
- ? - a number that is 15% of 45.
Further, there is a simplification of the fraction to the equation with one unknown. According to mathematical laws, cross-sectional data in proportions are equal to each other, that is: 45 * 15% \u003d? * 100%. To find “?”, We use a simple rule and get the following.
The calculation of the proportion formula always takes place on the principle of multiplying the known data standing diagonally and dividing them by the third number.
You can make a formula with any unknown in. In order not to get confused, the percentage or the number is the result, we recall the reduction rule in fractions - if the percent sign (%) or monetary symbol (rub) is present both above and below, it is reduced. Example:
As a result of the calculation, a sum of money is obtained.
How to find the percentage of the number. Options
Consider the order of the situation for finding interest.
How to find 100%. It is necessary to calculate a number, 15% of which is 45. We compose the proportion:
Calculated by the formula: (45 * 100) / 15 \u003d 300
If it is not known how much is 100%. Sometimes the calculation is carried out with respect to the same initial data, but their exact value is not known. For example: yesterday 15% of the total number of cookies in the amount of 450 rubles, and today 25%.
How much was sold today? Since the sum of 100% is the total for both 15% and 25%, it is possible to carry out calculations without searching for the full cost.
Calculated by the formula: (25 * 450) / 15 \u003d 750
You can complicate the task if there is no confidence in the calculations, or there is a need to verify the result. To do this, at first, be 100%, based on complete data (15% costs 450 rubles), and then 25% are counted from 100%.
How much less is the number in percentage
For example: the usual cost of a powder is 500 rubles. For shares, the price was reduced to 480 rubles. How much is the share price less than the initial percentage? First, find the percentage component of the promotional price from the base, and then find their difference. We make the proportion:
Calculated by the formula: (480 * 100) / 500 \u003d 96. 100% -96% \u003d 4%. The stock price is 4% lower than the original.
How much more is the number in percent. Example: a keyboard cost 300 rubles, and after increasing the dollar, the price rose to 390 rubles. How much has the keyboard price changed as a percentage? First, there is the total interest rate of the new price, relative to the original, then their difference is calculated. We make the proportion:
Calculated by the formula: (390 * 100) / 300 \u003d 130. 130% -100% \u003d 30%. Price increased by 30%.
An unknown number is more known by a certain percentage. Example: goods in a store, 15% more expensive than goods in a warehouse. The price of sugar in the warehouse is 50 rubles and is equal to 100%. Shop price - 100% + 15% \u003d 115%. Calculated by the formula: (115 * 50) / 100 \u003d 57.5
An unknown number is less than the known by a given percentage. Example: wholesale is 5% cheaper. The retail price is 60 rubles and is equal to 100 percent, for wholesale - 100% -5% \u003d 95%. We make the proportion:
Calculated by the formula: (60 * 95) / 100 \u003d 57
Percentage between two numbers. The situation when a number is known that is 100% and a number that makes up a fraction of the original. Example: a consignment of 60 boxes was expected, and 53 were delivered. By what percentage the plan was fulfilled. We make the proportion:
Calculated by the formula: (53 * 100) / 60 \u003d 88.3
The most difficult “task” is not to get confused in drawing up the proportion.
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The question "how to calculate interest" begins to overcome students in grade 5. It was then that such a topic appeared in mathematics. It seems that fifth graders are not offered complex tasks. Then why do many have problems with these tasks? Perhaps everything is hiding in a misunderstanding of the essence of this concept.
The foundation of everything is understanding.
This is the key to all tasks on this subject. If a person can determine one percent, then he can do thirteen, eighty nine and one hundred thirty five. At least four hundred and twenty ...
And this is the hundredth part of the total number that is discussed in the problem. Moreover, it can be set explicitly, but sometimes it is only indirectly discussed.
What are the situations?
Find out the percentage of the number
That is, a certain quantity is known and it is required to calculate how much x% of it will be. This is the main task in the topic. So how to calculate the percentage of the number? You need to make a proportion, the first line will contain the known data, the second - the desired. Now you need to multiply the known value by the desired percentage and divide by 100%.
If you write it shorter, you get the following proportion:
known number - 100%,
the desired number is x%.
From this record, you can make the formula:
unknown \u003d (known * x%) / 100%.
The result is obtained by crosswise multiplying two known quantities and dividing by the one that was left without a pair.
If the total number in the problem is made up of several, then the question arises of how to calculate the percentage of the amount. Here you can do two ways:
![](https://i0.wp.com/syl.ru/misc/i/ai/185664/769909.jpg)
Find out the number by a known percentage
In this situation, part of the number and the corresponding% are known. To find out how to calculate interest, you will need to use the already recorded proportion. Only in the first line will there be the desired number, and in the second - the known:
unknown \u003d (known * 100%) / x%.
Find out the percentage of one number from another
Two values \u200b\u200bare given, and you need to calculate how many percent will be more or less. Typically, such tasks contain information about an overfulfilled plan or, conversely, about a decrease in the amount compared to an earlier value.
Again, proportion is required. For 100%, it is customary to take the value with which they are compared.
the first value is 100%,
the second value is x%,
x \u003d (second value * 100%) / first value.
Find out the percentage when nothing is known about the total number
In such tasks, it is reported that a certain number is a known percentage, and another is an unknown percentage. Here it also needs to be calculated. How to calculate the interest in this case? Again using proportion:
the first number is known%,
the second number is x%,
x \u003d (second * known%) / first.
Tasks with more difficult questions
Find out how many percent the numbers differ
Two options are possible here. First, when you need to compare more with less. And find how many percent the second is less. In this situation, the question of how to calculate interest is reduced to understanding what to choose for 100%. The one that is larger. And then the proportion will look like this:
a larger number is 100%,
the smaller number is x%,
x \u003d (less than * 100%) / more.
But that is not the answer. For it, you will need to subtract the found x value from 100%.
The second option is when a smaller number is compared with one that is larger. In it, a smaller value is taken as 100%. The aspect ratio is as follows:
a lower number is 100%
the larger number is x%,
x \u003d (greater than * 100%) / less.
To calculate the final value, you need to find out how much x% - 100% will be.
Find out the result of increasing the number by a known percentage
In such tasks, you need to find the answer that will turn out after increasing the known percentage by a certain value. In this case, the proportion will look like this:
known number - 100%,
the desired number is 100 + x%,
desired \u003d (known * (100 + x%)) / 100%.
Find out the result of reducing the number by a known number of percent
known number - 100%,
the desired number is 100 - x%,
unknown \u003d (known * (100 - x%)) / 100%.
Calculator as an assistant in calculating interest
It can be used in two ways. The first is when all the above steps are performed in stages on the screen of the device. Everything is simple here. You just need not to get confused with the procedure. In general, a calculator will simply replace a person at the moment of practical calculation.
In the second method, he will do everything himself. For example, you can choose the engineering view of the calculator on the computer and enter the whole formula into it at once with brackets and necessary actions. After pressing the “\u003d” key, the answer will be displayed in the window.
It happens that the calculation option is simple when you need to know the percentage of a known value. Then you can use the special function, which is indicated by the "%" button.
To do this, you need to dial a known value on the calculator. Then press the multiplication sign. Then the number of percent and the "%" button. An answer will immediately appear on the screen.
They will allow you not to get confused. Moreover, it will be able to answer any question about how to calculate the percentage of the amount or difference, no longer have to think about it - everything will be decided automatically.
- Always move on to specific values. Percentage is something faceless. But the kilograms, students and boxes are quite tangible and understandable. They need to strive for.
- Read the condition very carefully. Because there are situations when interest is taken several times and from different values.
- Check the answer. Is he definitely finite? Or maybe this is just an intermediate value.
Math may not have been your favorite subject at school, and the numbers scared and saddened. But in adulthood there is no escape from them. Without calculations, do not fill out a receipt for payment of electricity, do not draw up a business project, do not help the child with homework. Often in these and other cases it is required to calculate a percentage of the amount. How to do this if vague memories have remained of school times about what is the percentage? Let's strain the memory and figure it out.
Method one: percentage of the amount by determining the value of one percent
Percentage is one hundredth of a number and is indicated by the% sign. If you divide the amount by 100, then just get one percent of it. And then everything is simple. The resulting number is multiplied by the desired number of percent. In this way, it is easy to calculate the profit on a deposit in a bank.
For example, you put an amount of 30,000 at 9% per annum. What will be the profit? The amount of 30,000 is divided by 100. We get the value of one percent - 300. We multiply 300 by 9 and get 2700 rubles - an increase to the original amount. If the contribution is for two or three years, then this indicator doubles or triples. There are deposits on which interest is paid monthly. Then it is necessary to divide 2700 into 12 months. 225 rubles will be a monthly profit. If interest is capitalized (added to the total account), then each month the deposit amount will increase. This means that the percentage will be calculated not from the down payment, but from a new indicator. Therefore, at the end of the year you will receive a profit not of 2700 rubles, but more. How many? Try to count.
Method Two: Convert Percentage to Decimal
As you remember, a percentage is a hundredth of a number. In decimal it is 0.01 (zero point one cell). Therefore, 17% is 0.17 (zero point, seventeen hundredths), 45% is 0.45 (zero point, forty-five hundredths), etc. Multiply the resulting decimal fraction by the amount, the percentage of which is calculated. And we find the desired answer.
For example, let's calculate the amount of income tax on salary of 35,000 rubles. The tax is 13%. In decimal it will be 0.13 (zero point, thirteen hundredths). Multiply the sum of 35,000 by 0.13. It will turn out 4,550. So, after deducting income tax, you will be paid a salary of 35,000 - 4,550 \u003d 30,050. Sometimes this amount is already called a “wage on hand” or “clean” without tax. In contrast, the amount along with the dirty salary tax. It is the “dirty salary” indicated in the vacancy announcements of the company and in the employment contract. On hands is less. How many? Now you can easily count.
Third way: count on the calculator
If you doubt your mathematical abilities, then use the calculator. With its help, it is considered faster and more accurate, especially when it comes to large amounts. It’s easier to work with a calculator that has a button with a percent sign. We multiply the amount by the number of percentages and press the% button. The screen will display the necessary answer.
For example, you want to calculate what your allowance for caring for a child under 1.5 will be. It accounts for 40% of average earnings for the last two closed calendar years. Let's say the average salary is 30,000 rubles. On the calculator, 30,000, multiply by 40 and press the% button. Key \u003d no need to touch. An answer of 12,000 will be displayed on the screen. This will be the size of the allowance.
As you can see, everything is very simple. Moreover, the “Calculator” application is now on every cell phone. If the device does not have a special% button, use one of the two methods described above. And multiply and divide on the calculator, which will facilitate and speed up your calculations.
Do not forget: to facilitate the calculations there are online calculators. They act in the same way as ordinary ones, but are always at hand when you are working on a computer.
The fourth method: we make the proportion
You can calculate the percentage of the amount by compiling a proportion. This is another scary word from a school math course. Proportion is the equality between two relations of four quantities. For clarity, it is better to immediately understand a specific example. You want to buy boots for 8,000 rubles. The price tag indicates that they are sold at a 25% discount. How much is it in rubles? Of the 4 values, we know 3. There is a sum of 8,000, which is equivalent to 100%, and 25%, which must be calculated. In mathematics, an unknown quantity is usually called X. The proportion is:
For the convenience of calculations, we convert percentages to decimal fractions. We get:
The proportion is solved as follows: X \u003d 8,000 * 0.25: 1X \u003d 2,000
2,000 rubles - discount on boots. Subtract this amount from the old price. 8,000 - 2,000 \u003d 6,000 rubles (new discounted price). Here is such a nice proportion.
This method can also be used to determine the value of 100%, if you know a numerical indicator - say, 70%. At the corporate meeting, the chief announced that 46,900 units of goods were sold during the year, while the plan was only 70% complete. How much did you need to sell to complete the plan? We make the proportion:
We translate percentages into decimal fractions, it turns out:
We decide the proportion: X \u003d 46,900 * 1: 0,7X \u003d 67,000. These are the results of the work that the authorities expected.
As you may have guessed, the proportion method can calculate how many percent is a numerical indicator of the amount. For example, when performing a test, you answered correctly 132 questions out of 150. How many percent of the task was done?
It is not necessary to translate this proportion into decimal fractions, you can immediately decide.
X \u003d 100 * 132: 150. As a result, X \u003d 88%
As you can see, it’s not so scary. A little patience and attention, and now you have mastered the calculation of interest.
How to calculate a percentage of the amount, you need to know in many cases (when calculating the state duty, credit, etc.). We will tell you how to calculate the percentage of the amount using a calculator, proportions and known ratios.
How to find out a percentage of the amount in the general case?
After that, there are two options:
- If you need to find out how much interest is another amount from the original, you just need to divide it by the size of 1% received earlier.
- If you need a size amount that is, say, 27.5% of the original, you need to multiply the size of 1% by the required number of percent.
How to calculate the percentage of the amount using the proportion?
But you can do otherwise. To do this, you will have to use knowledge about the method of proportions, which are held as part of the school course of mathematics. It will look like this.
Suppose we have A - the main amount equal to 100%, and B - the amount whose ratio with A in percentage we need to know. We write the proportion:
(X in this case is the number of percent).
According to the rules for calculating proportions, we obtain the following formula:
X \u003d 100 * V / A
If you need to find out how much amount B will amount to with the already known number of percent of amount A, the formula will look different:
B \u003d 100 * X / A
Now it remains to substitute the known numbers in the formula - and you can make a calculation.
How to calculate the percentage of the amount using known ratios?
Finally, you can use a simpler way. To do this, it is enough to remember that 1% in the form of a decimal fraction is 0.01. Accordingly, 20% is 0.2; 48% - 0.48; 37.5% is 0.375, etc. It is enough to multiply the original amount by the corresponding number - and the result will mean the size of the percent.
In addition, you can sometimes use simple fractions. For example, 10% is 0.1, that is, 1/10 therefore, to find out how much will be 10% is simple: you just need to divide the original amount by 10.
Other examples of such relationships will be:
- 12.5% \u200b\u200b- 1/8, that is, you need to divide by 8;
- 20% - 1/5, that is, you need to divide by 5;
- 25% - 1/4, that is, divide by 4;
- 50% - 1/2, that is, you need to divide in half;
- 75% - 3/4, that is, you need to divide by 4 and multiply by 3.
True, not all simple fractions are convenient for calculating interest. For example, 1/3 is close in size to 33%, but not exactly equal: 1/3 is 33, (3)% (that is, a fraction with infinite triples after the decimal point).
How to subtract a percentage of the amount without using a calculator
If it is required to subtract an unknown number of a certain amount from a certain amount, 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. For this, we subtract from 100% the number of percent that you want to subtract, and we translate the result from percent into a number using any of the methods described above.
The second example is more convenient, so we illustrate it. Suppose we need to find out how much will remain if 16% is taken from 4779. The calculation will be as follows:
- Subtract from 100 (total percent) 16. Get 84.
- We calculate how much will be 84% of 4779. We get 4014.36.
How to calculate (subtract) percentage from a sum with a calculator in hand
All of the above calculations are easier to do using a calculator. It can be either in the form of a separate device, or in the form of a special program on a computer, smartphone or regular mobile phone (even the oldest of the currently used devices usually have this function). With their help, the question of how to calculate the percentage of the amount is solved very simply:
- The initial amount is typed.
- The “-" sign is pressed.
- Enter the number of percent to be deducted.
- The sign "%" is pressed.
- The sign "\u003d" is pressed.
As a result, the desired number is displayed on the screen.
How to subtract a percentage from an amount using an online calculator
Finally, now there are enough sites on the network where the online calculator function is implemented. In this case, you don’t even need to know how to calculate the percentage of the amount: all user operations are reduced to entering the numbers in the windows (or moving the sliders to get them), after which the result is immediately displayed on the screen.
This function is especially convenient for those who calculate not just an abstract percentage, but a specific amount of tax deduction or the amount of state duty. The fact is that in this case the calculations are more complicated: it is necessary not only to find percentages, but also add to them a constant part of the amount. An online calculator avoids such extra calculations. The main thing is to choose a site that uses data that complies with applicable law.