Editing Percentage (section)

== Variants of the percentage calculation ==
The calculation of percentages is carried out and taught in different ways depending on the prerequisites and requirements. In this way, the usual formulas can be obtained with proportions, which saves them from having to remember them. In so-called mental arithmetic, the intermediary question is usually asked what 100% or 1% is (corresponds to).

Example:

42&nbsp;kg is 7%. How much is (corresponds to) 100%?<br />Given are ''W'' (percentage) and ''p'' % (percentage).<br />We are looking for ''G'' (basic value).
{| class="wikitable"
|-
!class="backgroundcolor3"| With general [[formula]]
!class="backgroundcolor6"| With own ratio equation ([[Quotient#Proportions|Proportion]])
!class="backgroundcolor4"| With “What is 1%?” ([[Rule of 3 (mathematics)|Rule of 3]]) <math>\frac{p\,\%}{42\,\text{kg}}=\frac{100\,\%}{7\ \%}</math>
|-
| <math>\frac{p\,\%}{100\,\%}=\frac{W}{G}</math><br /><br />multiple rearrangements result in:<br /><br /><math>G=\frac{W}{p\,\%}\cdot{100\,\%}</math><br /><math>G=\frac{42\,\text{ kg}}{7\,\%}\cdot{100\,\%}=600\,\text{kg}</math>
|<math>\frac{G}{42\,\text{kg}}=\frac{100\,\%}{7\,\%}</math><br /><br />simple conversion yields:<br /><br /><math>G=\frac{42\,\text{kg}}{7\,\%}\cdot{100\,\%}=600\,\text{ kg}</math>
| <math>\frac{42\,\text{kg}:{ \color{red}7}}{7\,\%:{ \color{red}7}}=\frac{6\,\text{ kg}}{1\,\%}=\frac{6\,\text{kg}\cdot { \color{red}100}}{1\,\%\cdot { \color{red}100}} </math><br /><br />without changing the last counter is:<br /><br /><math>G=6\,\text{kg}\cdot 100=600\,\text{ kg}</math>
|-
|class="backgroundcolor3"| Advantage:<br />•&nbsp;One formula for all tasks<br />
|class="backgroundcolor6"| Advantages:<br />•&nbsp;Without a formula<br />•&nbsp;Easy to change over if the size you are looking for –&nbsp;here ''G''&nbsp;– is in the top left of the counter.<br />
|class="backgroundcolor4"| Advantages:<br />•&nbsp;Without a formula<br />•&nbsp;Simple rule of three&nbsp;– here as a chain of equations<br />•&nbsp;Application for mental arithmetic
|}