Advice 1: How to learn percentages

The concept of "interest" (means "hundredth") is widely spread in science, technology and everyday life. Very often this term is found in the economy, especially in statistics and accounting. Percent believe the payroll taxes and premiums. Not learning how to properly consider interest, it is not necessary to go to the Bank for a loan. Even discounts in the store is impossible to calculate without understanding the interest. It is especially important to learn to consider the interest someone who runs his own business.
How to learn percentages
You will need
  • calculator
Instruction
1
To learn how to count percentages, remember that one percent is one hundredth of something. In most cases the amount of interest does not exceed one hundred. However, the percentage may be more than a hundred – this result does not Always indicate an error, but only a reason to double-check the correctness of the calculations.
2
If you set the amount (quantity) of something whole (kg) and value (number) part of the whole (CH), the answer to the question: "what percentage of H from C, divide H by C and multiply by 100.
H/C*100
Example
An employee's salary – 30 000 roubles. He was given a prize – 3000 rubles.

Question: what percentage was the prize of the salary?
The decision: 3000/30000*100=10 (%).
Interest is a dimensionless quantity. Therefore, it is important that the calculations, all quantities have the same dimension (more precisely, so that eventually all units reduced). For example, if in the previous example, the award was issued in dollars, they must be first translated into rubles.
3
If you set the amount (quantity) of something whole (n) and percentage (To), to answer the question: "what is To percent of C, divide C by 100 and multiply by K.
C/100*
Example
The voltage is 220 Volts. The maximum deviation from the nominal voltage value is 5%.

Question: how many volts can change the voltage?
Solution: 220/100*5=11 V (Volts)
4
If you set the amount (quantity) of something whole (n) and percentage (To) at which the magnitude of C increased (decreased), then the answer to the question: "what was equal to a new value C, add (or subtract, if TS lowered to C her hundredth multiplied by K.
TS+TS/100*K (TCH/100*K)
Example
The farmer takes a Bank loan for one year – 100,000 rubles. The interest rate is 20% per annum.

Question: what amount will have to pay the farmer if the loan is repaid in a year in a lump sum?
Solution: 100000 + 100000/100*20 = 120000 (RUB).

Advice 2 : How to add to the amount interest

If you want to calculate a value that is obtained by adding to some source the amount of money specified percentage, it is rather simple math problem. It can be solved using any calculator or just in the mind. And you can not use neither that, nor this, and ask the Internet modern levels of development of communications and computing technology allow you to keep your mind clear for more important things.
How to add to the amount interest
Instruction
1
If you choose to add a percentage to the amount using their own mathematical abilities, start with the formulation of the forthcoming mathematical operations, as the correct formulation of the problem in any case is half of its solution. Assume that the percentage is one-hundredth share of the available amount. To Express the size of this one hundredth in monetary units need the entire sum to be divided into one hundred. For example, one percent of the amount of one hundred thousand rubles will amount to one thousand rubles. So, the original amount with the added percentage will be one hundred one thousand rubles. If such interest is necessary to add several (e.g. ten), then the amount of one percent (thousand rubles) it is necessary to tenfold (ten thousand) and added to the original amount (total: one hundred ten thousand rubles).
2
If to add to the amount of interest you decide to use any calculator, do not forget that in Windows there are apps of this kind. Run it through the main menu on the "start" button - in the menu go to "All programs", then to "Standard", then in the section "Service" and choose "Calculator". Although you can not go so far, and press the key combination win + r, calc score and click on the "OK" button. C using a calculator, you can solve this puzzle in several ways. For example, enter the original amount, click the division button, enter 100, then click multiply and enter the amount of interest. Then click on the summation and re-enter the original amount and then press Enter. The number in the window of the calculator will be the amount with the added interest.
3
If you trust to calculate the amount of added cent the Internet, then it can be done even from your mobile phone. Go, for example, search engines such as Google and specify in the search query box of the desired mathematical operation. For example, if you need to add to the original amount of one hundred thousand is 10%, enter this search query: "110% of 100000". The mighty intellect of a search engine will immediately calculate and present the results to you.
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