How to find out from the amount. School mathematics. How to find the percentage of a number
Example 1
You go to the supermarket and see a promotion for . Its regular price is 458 rubles, now there is a 7% discount. But you have a store card, and according to it, a pack will cost 417 rubles.
To understand which option is more profitable, you need to convert 7% into rubles.
Divide 458 by 100. To do this, you simply move the comma separating the integer part of the number from the fractional part two positions to the left. 1% is equal to 4.58 rubles.
Multiply 4.58 by 7 and you get 32.06 rubles.
Now all that remains is to subtract 32.06 rubles from the regular price. According to the promotion, coffee will cost 425.94 rubles. This means that it is more profitable to buy it with a card.
Example 2
You see that the game on Steam costs 1,000 rubles, although it was previously sold for 1,500 rubles. You are wondering what percentage the discount was.
Divide 1,500 by 100. Moving the decimal point two places to the left gives you 15. That's 1% of the old price.
Now divide the new price by 1%. 1,000 / 15 = 66.6666%.
100% – 66.6666% = 33.3333%. This discount was provided by the store.
2. How to calculate percentages by dividing a number by 10
First you find the size of 10% and then divide or multiply it to get required quantity percent.
Example
Let's say you deposit 530 thousand rubles for 12 months. The interest rate is 5%, capitalization is not provided. You want to know how much money you will get in a year.
First of all, you need to calculate 10% of the amount. Divide it by 10 by moving the decimal place one place to the left. You will receive 53 thousand.
To find out how much 5% is, divide the result by 2. That's 26.5 thousand.
If the example was 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, it is quite easy to operate with such large numbers.
3. How to calculate percentages by making a proportion
Making proportions is one of the most useful skills taught to you in . You can use it to calculate any percentage. The proportion looks like this:
amount constituting 100% : 100% = part of the amount: share as a percentage.
Or you can write it like this: a: b = c: d.
Typically, proportion is read as “a is to b as c is to d.” The product of the extreme terms of a proportion is equal to the product of its middle terms. To find out the unknown number from this equality, you need to solve the simplest equation.
Example 1
For an example of calculations, we use the recipe. You want to cook it and you bought it suitable tiles chocolate weighing 90 g, but couldn’t resist and took a bite or two. Now you only have 70g of chocolate and you need to know how much butter to put instead of 200g.
First, calculate the percentage of chocolate remaining.
90 g: 100% = 70 g: X, where X is the mass of the remaining chocolate.
X = 70 × 100 / 90 = 77.7%.
Now we make a proportion to find out how much oil we need:
200 g: 100% = X: 77.7%, where X is the required amount of oil.
X = 77.7 × 200 / 100 = 155.4.
Therefore, you need to put approximately 155 g of butter 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 up the proportion: 1,499: 100 = X: 87.
X = 87 × 1,499 / 100.
Pay 1,304.13 rubles and wear the blouse with pleasure.
4. How to calculate percentages using ratios
In some cases, you can use simple fractions. For example, 10% is 1/10 of a number. And to find out how much it will be in numbers, just 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. This means you have to divide the number by 4 and multiply by 3.
Example
You found trousers for 2,300 rubles with a 25% discount, but you only have 2,000 rubles in your wallet. To find out if you have enough money for a new thing, carry out a series of simple calculations:
100% - 25% = 75% - the cost of the trousers as a percentage of the original price after applying the discount.
2,400 / 4 × 3 = 1,800. That’s how many rubles the pants cost.
5. How to calculate interest using a calculator
If life is not pleasant for you without a calculator, all calculations can be done with its help. Or you can do it even simpler.
- To calculate a percentage of an amount, enter the number equal to 100%, the multiplication sign, then the desired percentage and the % sign. For the coffee example, the calculation would look like this: 458 × 7%.
- To find out the amount minus interest, enter a number equal to 100%, a minus, the size of the percentage and the % sign: 458 - 7%.
- You can add up similarly, 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 percentages. There are services for lenders, investors, entrepreneurs and all those who do not like to do math in their heads.
A percentage is one hundredth of a number taken as a whole. Percentages are used to indicate the relationship of a part to the whole, as well as to compare quantities.
1% = 1 100 = 0,01
The interest calculator allows you to perform the following operations:
Find the percentage of a number
To find the percentage p from a number, you need to multiply this number by a fraction p 100
Let's find 12% of the number 300:
300 12
100
= 300 · 0.12 = 36
12% of 300 is 36.
For example, a product costs 500 rubles and there is a 7% discount on it. Let's find the absolute value of the discount:
500 7
100
= 500 · 0.07 = 35
Thus, the discount is 35 rubles.
What percentage is one number of another?
To calculate the percentage of numbers, you need to divide one number by another and multiply by 100%.
Let's calculate what percentage the number 12 is from the number 30:
12
30
· 100 = 0.4 · 100 = 40%
The number 12 is 40% of the number 30.
For example, a book contains 340 pages. Vasya read 200 pages. Let's calculate what percentage of the entire book Vasya read.
200
340
· 100% = 0.59 · 100 = 59%
Thus, Vasya read 59% of the entire book.
Add percentage to number
To add to a number p percent, you need to multiply this number by (1 + p 100)
Add 30% to the number 200:
200 (1 + 30
100
) = 200 1.3 = 260
200 + 30% equals 260.
For example, a swimming pool subscription costs 1000 rubles. Starting next month they promised to raise the price by 20%. Let's calculate how much a subscription will cost.
1000 (1 + 20
100
) = 1000 1.2 = 1200
Thus, the subscription will cost 1200 rubles.
Subtract the percentage from the number
To subtract from a number p percent, you need to multiply this number by (1 - p 100)
Subtract 30% from the number 200:
200 (1 - 30
100
) = 200 · 0.7 = 140
200 - 30% equals 140.
For example, a bicycle costs 30,000 rubles. The store gave it a 5% discount. Let's calculate how much the bike will cost taking into account the discount.
30000 · (1 - 5
100
) = 30000 0.95 = 28500
Thus, the bike will cost 28,500 rubles.
What percentage is one number greater than another?
To calculate how many percent one number is greater than another, you need to divide the first number by the second, multiply the result by 100 and subtract 100.
Let's calculate what percentage is the number 20 more number 5:
20
5
· 100 - 100 = 4 · 100 - 100 = 400 - 100 = 300%
The number 20 is 300% greater than the number 5.
For example, the salary of a boss is 50,000 rubles, and an employee’s salary is 30,000 rubles. Let's find out how many percent the boss's salary is greater:
50000
35000
· 100 - 100 = 1.43 * 100 - 100 = 143 - 100 = 43%
Thus, the boss's salary is 43% higher than the employee's salary.
What percentage is one number less than another?
To calculate how many percent one number is less than another, you need to subtract from 100 the ratio of the first number to the second, multiplied by 100.
Let's calculate what percentage is the number 5 less number 20:
100 - 5
20
· 100 = 100 - 0.25 · 100 = 100 - 25 = 75%
The number 5 is 75% less than the number 20.
For example, freelancer Oleg completed orders worth 40,000 rubles in January, and 30,000 rubles in February. Let's find how many percent less Oleg earned in February than in January:
100 - 30000
40000
· 100 = 100 - 0.75 * 100 = 100 - 75 = 25%
Thus, in February Oleg earned 25% less than in January.
Find 100 percent
If the number x This p percent, then you can find 100 percent by multiplying the number x on 100p
Let's find 100% if 25% is 7:
7 · 100
25
= 7 4 = 28
If 25% equals 7, then 100% equals 28.
For example, Katya copies photos from her camera to her computer. In 5 minutes, 20% of the photos were copied. Let's find how long the copying process takes:
5 100
20
= 5 5 = 25
We find that the process of copying all photos takes 30 minutes.
Good day, dear guests! Did you do well at school? I'm excellent, but I also have situations when I need to brush up on my school knowledge.
Unfortunately, among the entire volume of information, it is very difficult to identify the information that may actually be needed.
Let's remember today how to find out the percentage of a number.
Mathematics is necessary in everyday life, because it teaches you to think outside the box and develops logic. Knowledge of computational manipulation makes life easier financially.
Here are examples of using %:
- This ratio allows you to improve the perception of information in order to compare certain parameters. For example, the human body consists of 70% water, and jellyfish - 98%.
- Such calculations are also used in economics. This is necessary, for example, for profit calculations.
- Knowledge is also necessary for analyzing specific quantities. For example, the difference between salaries in different months.
Interest concept
Interestingly, the Hindus used percentages in calculations back in the 5th century. In Europe about decimals found out only after a millennium.
This concept was introduced by a Belgian scientist Simon Stevin. In the 16th century, a table with values was published.
The word itself is of Latin origin. The word is translated as “from a hundred.” This means one hundredth of any value.
% provide the opportunity to compare the components of one whole without difficulty. The emergence of shares made calculations easier and they became standard.
Calculation methods
In the 5th grade mathematics textbook you can find out that % is a hundredth of a number. To find out what % of a certain value you can use proportion and create a cross rule.
For example, you need to find 500 from 1000. In this case, the data that is located opposite each other must be multiplied and then divided by the third number.
In this case, numbers are written under the numbers, and percentages under the same indicators.
It turns out:
1000 – 100%;
500 – x%.
We get: X=(500*100)/1000.
X=50%.
You can also use Excel.
For example, you need to find the amount that is 15% of the whole number 8500.
First, create an Excel sheet on your desktop.
Then open the document and in the highlighted line enter:
- = (equal);
- then 8500;
- after that press * (multiply);
- then 15;
- Then press the % and Enter keys.
How to calculate percentage on a calculator
Then you need to enter the requested data in the fields and get the result. In this case, you can find out how % of total number, and what percentage the value of one number is from another.
To summarize, we can say that the calculator allows you to decide on the following questions:
- Calculate a specific % from a specific value. Or, if % is known, then add it to some number.
- What % is of the given indicator.
- How many % does one value contain from another.
A regular calculator also has a function for determining %. If there is an option, then there should be a key where %.
To do this, find the percentage (%) button on his keyboard.
For example, let's find out how much 12 is from 125.
To do this, we will carry out the following manipulations:
Enter 125 on the calculator.
Click multiply (*).
Press 12.
Then click the percentage button.
In this case, the result will be displayed on the screen - 9.6%.
This way you can find any other values with two numbers. You can also use the calculator on your mobile phone.
On a laptop or computer, you can find useful programs through the start menu.
Calculation using formulas
So, let's look at some formulas for calculation.
Formula for calculating percentage of a certain value.
If the number A and the percentage component of B are known, then the percentage of A is found as follows:
B=A*P/100%.
There is a special formula for calculating percentages. In this case, you need to find out from what value %.
If B is known, which is P percent of the number A, then the quantity A is found like this.
A=B*100%/R.
You can also calculate the percentage of one number from another. If two values A and B are known, then you can find out what % B contains of A. The following formula is used. P=B/A*100%.
To find out how much the number has increased compared to the original, there is also a certain formula.
If the number A is known and it is necessary to find B, which is a certain percentage greater than the number A, then the following formula is applied: B=A(1+P/100%).
There is also a formula for calculating which is less than the original by a certain percentage.
If we know the number A and it is necessary to find B, which is P% less than A, then the following calculation is used: B=A(1-P/100%).
I hope you find the information in my article useful. If you want to add to it, write in the comments.
Remember your school knowledge and use it in everyday life. Mathematical calculations make life a lot easier.
That's all I have for today. Goodbye, dear fans of my blog!
The word "percentage" in Greek means the hundredth part of a number. In mathematics, and throughout the world, it is customary to consider the absolute as 100%. Based on this principle, all computational rules are built.
There are several options for tasks related to the goal of counting. Each such task has its own individual solution principle.
The problem statement gives a certain numeric value and you need to find its percentage. For example, we have the number 47 and we need to calculate its 25%.
Solution: To solve, we take the original number as 100%. After this, we convert this percentage to and get that 25% = 0.25. We multiply 47 by the percentage expressed as a fraction and get the desired number 47*0.25=11.75.
Answer: 11.75 is 25% of 47.
Find a number by percentage
The next type of problem related to the question of how to find the percentage of a number is calculating the value from the existing percentage. It is given that 57 is 45% of some number. You need to find this number.
Solution: To solve this problem, you need to divide the available number by the percentage it makes up of the whole. So, we get that 57/0.45=126.67. To better understand this action, it would be useful to analyze 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 percent. It turns out that 1% of the whole number is 1.2667. Next, to find the integer, we multiply the resulting value by 100.
Answer: A number whose 45% is 57 is 126.67.
Find what percentage one number is of another
A little more difficult are tasks in which you need to find the percentage value that one number makes of another. How to find the percentage of a number in this case? The answer is very simple. Let's look at it with a small example. We have two numbers: let's say it's 45 and 58. To find out what percentage 45 is of 58, we need to multiply it by 100 and divide by 58. We get that 45 is 77.6% of 58.
You often see situations where people do not understand how the price of a product will change if it increases by 15%. People forget basic school mathematics and for this reason they wonder how to find the percentage of a number.
Knowledge of percentage messages in the field of exchange communications and operations is especially important. When making deposits we also deal with interest. There the principle of floating interest or capitalization often applies, which slightly complicates the principle of calculating the final result.
As we can see, with a little repetition you can easily remember, or relearn, how to find the percentage of a number, and indeed, how to work with such a mathematical and financial unit. This knowledge will not only expand the general human horizons, but will also help to more confidently navigate situations with changes in prices, exchange rates, profit margins and other very important processes. Of course, at first glance it seems that the ability to do mental calculations can save only a few seconds, but a minute gained from making one decision can result in several freed days over the course of a year.
In this article we will describe how find the percentage of a number, the proportion of one number to another. Somewhere in the fifth grade, during entertaining mathematics lessons, children begin to study such a topic as "interest". Then a fascinating world of percentages and fractions opens up for those who love to count. Teachers give a significant number of interesting, exciting problems to solve involving determining percentages. But during school years, children think that they will not necessarily need this knowledge, but in vain! After all, this topic is always relevant and is closely related to everyday life and may well be useful in various life situations.
Why is it important to be able to find percentages of numbers?
Everyone definitely needs to be able to calculate percentages. You may ask why? It’s just that any person almost every day comes across prices for goods and services in certain enterprises and establishments. Almost every second person has a loan, an installment plan, many have savings deposits in banks, and perhaps even more than one. Taxes, insurance, purchases - almost everything in our world involves interest. This topic concerns both financial, economic and other areas of our lives. But when solving children's problems from textbooks in grades 5-6, there are not as many pitfalls as when calculating an adult loan.
The school curriculum includes 3 patterns to solve problems in percentages:
finding percent from the number;
finding percentage numbers
finding the number itself based on its percentage.
Do not forget that calculating interest is very often used in everyday life. An example of this is using them in your family's budget calculations. Many families take out loans such as: “Car loan”, “Consumer loan”, “Education loan” and of course “Housing loan”, which also has another name that is more familiar to us - “Mortgage”.
How is percentage of a number indicated?
It is known that the percentage is indicated by the icon «%» . Different definitions of the term are used.
- The first one is known to everyone: a percentage is one hundredth of a number.
- The second is the fee charged by the bank or other persons issuing financial assets on credit for their use. This concept is extremely common for people in everyday life.
Percentage of a number - the history of the origin of the concept
Few people have wondered where this term came from. But the word “percentage” comes from the Roman Empire. Word "pro centum" can tell you little about it. But its literal designation means “from a hundred” or “for a hundred.” The very idea of expressing parts of a whole in many equal shares was born a long time ago in ancient Babylon. Back then, people used sexagesimal fractions in their calculations. People who lived in Babylon left us “as a souvenir” registers, from which they calculated interest to calculate the amount of debt “accumulated” by interest from the borrower.
Interests were extremely famous even in other states of Antiquity. People who knew the exact science of mathematics in India calculated percentages using the triple rule and used proportions in their calculations. The Romans, for example, were professionals in this field, because they called interest the money that the defaulter is forced to return to the one who issued it, and for every hundred. Even then, the Parliament of Rome adopted the maximum permissible interest that was taken from the debtor, because there were cases when lenders tried too hard to get their interest money. And it was from the Romans that the concept of interest passed on to all other peoples.
Who needs to know how to calculate interest?
- Accountant. He just needs to know how to calculate percentages. In any company, at any job, there is a person involved in accrual wages. Calculating, subtracting, multiplying your hard-earned money, earned through honest labor. Who is this? Of course an accountant. For example, he deals with the deduction of a percentage of wages. This percentage is a tax that is at the moment is 13% of income.
- Bank employee. He also just needs to know the percentage. For what? Yes, because it is this employee who deals with loans, mortgages, and financial investments. He calculates where people's money goes. Provides information about how much a person will overpay or receive during a transaction with the bank.
- Oculist. A doctor examining the fundus of the eye, studying how well a person sees. It determines vision. He will write out glasses. But with vision, as with glasses, not everything is so simple - we are all individual, and accordingly, our vision is different. Some have +(-) 1, and some have +(-) 0.75. And the ophthalmologist, like no one else, knows a lot about this. And not only education, but also knowledge of the percentage helps him understand this.
Application of finding percentages in different areas
Financial. Everything is elementary here - this is the same amount that the borrower pays to the lender for what the second provided to the first cash for temporary use. In this case, both persons negotiate the conditions of issuance in advance and individually, documenting the financial relationship.
Business vocabulary. In business there is such a concept - “work for interest.” This means that a person is ready to work and receive remuneration, which is calculated from the profit and turnover of the enterprise.
Significance in economics. A certain amount of profit that the “lender” pays to the “lender” for money capital borrowed. The source of interest is surplus value, which is formed by using its loan capital.
Loan interest. This is a kind of deduction for the temporary use of finances. A category that functions in credit relations. In short, this is a relationship between the lender and the borrower, where each has their own interest in finding and receiving interest. This is not a loan, because the loan interest is only the cost of the profit from the product. It turns out that the interest itself is simply a deduction of profit from the amount that is at the borrower’s disposal.
Deposit interest. Interest deduction for saving cash in storage facilities that a bank or other borrower takes out. There are two participants in this relationship. The first person (lender) is the bank's client, the second (borrower) is the bank itself.
How to find percentages - formula for finding percentage of a number (2 formulas with examples)
There are two simple formulas for finding percentages of a number:
1. The first formula is how you can calculate the percentage of a number - divide the desired number by one hundred and multiply by the number of percentages that is necessary.
X/100*Y=...
Where X is the total number from which the percentage is to be extracted, Y- the desired percentage of it.
Example from life: You need to transfer 300 rubles to a relative in Kamchatka. You used the Zhmotfinance payment system, in which the transfer fee is 16% of the payment amount. Thus, we need to find out how much 16 percent of the number 300 will be. Divide 300 by 100 and multiply by 16. (300/100*16) = 48. This will be the amount that the greedy payment system will take for itself.
2. And the second, more simple formula- multiply the number from which you need to extract (X) by 0,Y - where Y - this is the number of desired percentages, you will get the required amount of interest.
X* 0, Y... =
Where also: X - total number, Y - the desired percentage of it.
Example from life: Let's say you again contacted the Zhmotfinance company, which is ready to transfer your funds to anywhere in Russia for the same 16%. But now you need to send another amount to another relative living in Vladivostok - 500 rubles. This means that we need to get a percentage of the number 500. To do this, we simply multiply 500 by 0.16 (500*0.16) = 80. The extortionate 80 rubles as interest for the transfer go to the income of this greedy company.
Finally, remember - algebra, geometry, physics, chemistry and many other sciences will always be useful to you. And learning to find the percentage of a number may even benefit you in the future. Numbers and numbers play vital role in the future of man. And the ability to find percentages of any number in your mind can make your life much easier and help you avoid awkward and awkward situations in everyday life.
