Inverse proportionality
In inverse proportionality, as the value of one variable increases, the value of the other variable decreases in the same proportion. This can be applied to calculating speed and time, area calculations, resource allocation, calculating the number of employees, and many other practical matters. You can use the calculator on this website to calculate calculations based on inverse proportionality.
Direct Proportionality
In direct proportionality, the relationship between two variables remains the same. This can be applied to pricing, estimating distance and time, image size changes, and many other practical matters. The calculator on the page makes it easy to perform calculations based on direct proportionality.
Roundings in VAT calculation: Mathematically impossible prices?
There are a whole range of VAT-inclusive prices that cannot be mathematically arrived at if the tax is calculated from the VAT-free price. One example is 3.99. These prices are also possible, but then the VAT-free price must be interpreted as rounded.
Percentage calculations without a calculator
Percentage calculations become much easier when we understand that they are multiplication calculations. You can put the numbers to be calculated in a different order. You can also separate the tens and hundreds into their own numbers.
Negative percent
A percentage calculation can easily result in a negative percentage instead of a positive percentage. You can also calculate a percentage from a negative number. The calculation gets a bit strange when you calculate the percentage change using a negative number, but that's not impossible either.
Percentage and percentage point
A percentage means a hundredth and they are used to measure a share of something. The percentage point, on the other hand, is used when comparing percentages to each other or when referring to percentages of certain percentages.
In Europe there is VAT - in the US sales tax
In Europe, companies belonging to the production chain account for the VAT paid by the consumer to the state in proportion to their value added. The US sales tax, on the other hand, is billed entirely by the company that made the consumer sale. Sales tax is paid to local operators, not to the state.
History of taxation
Many of today's taxes were already in use in Antiquity. Deciding on taxation has moved from autocrats to parliaments and the level of taxation has risen. In earlier times taxes were used to wage wars, today taxes are used to maintain welfare states.