# Percentages

The percentage of something is one hundredth of it. That is, 1% = 1/100 = 0,01. The decimal form of a percentage will be used to calculate percentages.

**E****xample**** 1**

**1% = 0,01**

**13% = 0,13**

**57% = 0,57**

**100% = 1,00**

**123% = 1,23**

**_________________**

**0,14 = 14%**

**2,34 = 234%**

**0,005 = 0,5%**

**23,00 = 2300%**

**1,09 = 109%**

It is easy to calculate percentages in decimal form. For example, 20% of 50 is 0,2 · 50 = 10. So we multiply the number by a decimal form of percentage.

**Example 2**

Calculate 7% of 490.

Convert a percentage to a decimal form. 7% = 0.07

**0.07 · 490 = 34.3**

A percentage equation consists of three parts: the Original value, the Percent coefficient and the Result.

**Example 3**

*Let's calculate how much is 20% of 120.*

Original value = 120

Percent coefficient = 0,2

Result = *x*

The equation is obtained by multiplying the original number by a percentage coefficient equal to the result:

**0.2 · 120 = ****x**

24 = x

*Calculate 25% of 40?*

Original number =* x*

Percent coefficient = 0,25

Result = 40

Now, we do not know the figure from which 25% has been taken from. So we mark it as unknown by the letter *x*. However, the equation is formed in exactly the same way.

**0,25 · x = 40 || : 0.25**

*x* = 40 / 0,25

*x* = 160

*What percentage is 30 of 270?*

Original number = 270 (That is, what we compare to)

Percent coefficient = *x*

Result = 30 (What we compare)

**x**** · 270 = 30 || : 270**

*x* = 30/270

*x* ≈ 0.1111 ≈ 0.11 = 11%

Most percentages can be calculated this way. All you have to do is identify the number or value we are starting from, that is, where the percentage is from.

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