How to calculate a percentage

# How to calculate a percentage

## Contents

• 1 per cent concept
• 2 Calculate the percentage
• 2.1 How to convert any number to a percentage
• 2.2 How to calculate the percentage increase
• 2.3 How to calculate the percentage decrease
• 2.4 The difference between the percentage change and the rate of increase
• 3 Calculate the price after the discount
• 4 Percentage and measurement errors
• 5 percent use areas
• 6 video on how to calculate a percentage
• 7 References

## Percent concept

The percentage can be defined as the process of writing the number divided by a hundred (that is, a fraction is the numerator of the number , and its denominator is equal to the number of hundred), and this percentage is denoted by the symbol% ​​which means (from 100), (100 /), or (÷ 100), For example 8% means (8 out of 100), (8/100), or (8 ÷ 100), [1] and the word Percent is taken from the Latin word Per Centum, which means from one hundred , [2] The following table shows examples of percentages: [3]

## Calculate the percentage

### How to convert any number to a percentage

A percentage is defined as the process of assigning any number to a hundred, and any number can be converted to a percentage by the following: [4]
• Percentage calculation system: can calculate the ratio percentage of a system by dividing the number of individuals you want to know the proportion of the total number of individuals involved in the study, and hit the final output by 100, and can be represented
• y the equation:
The percentage of individuals within a system = (the number of individuals whose percentage ÷ is known الكلي the total number of individuals) * 100
• Calculating the percentage of a fraction: Any fraction consists of the numerator and denominator, where the numerator is the number at the top, and the denominator is the number at the bottom, and when we want to convert the fraction to a percentage, this means that we want to make the denominator equal to 100, so we multiply the number in The denominator by any other number makes it 100, and we multiply the numerator by this number, in order to keep the value of the fraction unchanged.
• Calculating the percentage of a decimal: This is the simplest process. For converting a decimal to a percentage, we just multiply that number by a hundred and add the% sign.

### Method for calculating the percentage increase

The increase in the percentage is calculated by calculating the difference between the value after the increase and the original value and then dividing the result by the original value, and multiplying the total by 100, and if the value of the increase is negative, the percentage decreases and does not increase, and can be represented by the formula: [5]
% Increase = ((value after increase - original value) الأصلية original value) * 100%

### Method for calculating the percentage decrease

The decrease in the percentage is calculated, either by using the same equation for the increase in the percentage with taking the absolute value of the final answer, or by calculating the difference between the original value and the value after the decrease and then dividing the result by the original value, and multiplying the total result by 100, and if the value of the decrease Negative, the percentage increases and does not decrease, and can be represented by the formula: [5]
Decrease in percentage = ((The original value - the value after the decrease) الأصلية the original value) * 100%

### The difference between the percentage change and the rate of increase

Some people confuse the rate of increase with the percentage change, and the difference between them can be explained as follows: [6]
• Increase rate: is the average change in the value of an object over a specified period of time. It can be represented in the formula:
Rate of increase = (((the second value of something at the second time - the first value of something at the first time) ÷ time period)) ÷ the first value of something at the first time) * 100%
• Percent change: It is the relative change in the value of an object over a specific period of time, and it can be represented in the formula:
Percentage change = ((the second value of the thing at the second time - the first value of the thing at the first time) الأولى the first value of the thing at the first time) * 100%

## Calculate the price after the discount

The percentage relates to the sale price after the discount, so an individual must first understand the percentage in order to be able to calculate the price of goods after the discount, and then he can apply the following law: (The sale price after the discount = the original price x (1 - the discount rate)), and it must be The percentage of deduction in this law is in the form of a decimal number. It is possible to facilitate understanding the previous law through the following steps: [7]
• We calculate the percentage of the sale price, that is, we must calculate the percentage that we will pay to buy the commodity, by subtracting the percentage of the discount from 100%, if the percentage of discount on a commodity is equal to 10%, we subtract it from 100%, to find the value of the percentage The selling price is equal to 90%.
• We convert the percentage of the sale price to a decimal, that is, we divide the result of the previous point by a hundred, and the decimal number of the above equals 90/100 = 0.9.
• We multiply the resulting decimal number by the original price of the piece. If the price of a piece, for example, is \$ 60, we multiply that price by 0.9, to produce \$ 54, which is the price of the piece after the discount .

## Percentage and measurement errors

Measurement errors are defined as the difference between the existing real value and the value measured using the measuring tools , and these errors are produced either because of an error in the measuring instrument, or the reading error of the person performing the measurement, and the greater the error rate in the measurement, the worse the reading, and errors are often measured The measurement is in percentage, such as saying the error rate (1%) or (10%) and so on. [8]

## Percentage usage areas

The percentage can be used in many areas, including: [1] [9] [10]
• The amount of discount on a commodity in a store.
• Rate of bank interest .
• Inflation rate .
• Miscellaneous statistics .
• The percentage of voters in elections .
• Companies describe their profit ratios.
• Commission given to an employee according to his percentage of work.