This article Not a part from my must-have app series. Is about **a small tribute to the KDE calculator** (And by extension to the other calculators on the other desks) I wrote it at first because I think almost no one uses them. However, behind them there are developers who dedicate their time to improving them.

There is a story, probably false, that establishes a causal relationship between the size of two horses' butts cycling at the same time and the diameter of the first rockets to reach the Moon. True or not, the moral is that **Many times things continue to be done that no longer have a reason to exist.** and, the inclusion of calculators in desktop operating systems may be a good example.

After all, they have been with us since 1985 when they appeared in Windows 1.0.

## Small tribute to the KDE calculator

A calculator application has a reason to exist on a smartphone. There are several situations in which we may need to make a more or less extensive account and we do not have a computer at hand. I would almost say it also makes sense on Windows which doesn't have a pre-installed spreadsheet like most distributions. **But the distributions usually include LibreOffice Calc and calculations can also be done from the terminal** using for example the echo command and the operation between square brackets

`echo $[ 45 * 15-6/2 ]`

A more powerful command **It is bc that allows us to perform the 4 basic operations in addition to calculating powers and square roots.**

To operate with this command we first write *bc*, press enter and then the operation. Example

bc

Scale=2

2*5/3

The first command indicates that it must give the result with two decimal places since if the division is not exact it will only give us the whole number.

### The KDE Calculator

Some of the features of the KDE calculator are:

- Allows you to copy and paste numbers to and from other applications or the computer screen.
- It has a stack of results that allows us to resume previous operations.
- It can operate with trigonometric functions, statistical calculations, and logical operations.
- Colors and typography are configurable.
- It is possible to determine the precision of the calculations and the number of decimals to work with
- You can use preset keyboard shortcuts and configure others.
- It is used from the keyboard or by clicking on the on-screen keys with the mouse pointer.

### Modes of use

The KDE calculator (Known by the unoriginal name Kcalc) has four different modes that vary according to the operations you want to perform. The mode change is done from the Preferences menu

#### Simple mode

**Allows you to perform basic operations** (Addition, subtraction, multiplication, division, calculation of percentages, use of parentheses and change of sign).

#### scientific mode

Buttons are added here for the **calculation of trigonometric functions (sine, arcsine, tangent, tangent and arctangent) calculation of logarithms and algebraic functions (calculation of the remainder in a Euclidean division, integer part of a quotient, reciprocal of a number, binomial coefficient, factorial, square or square root of X)**.

#### Statistical mode

In this mode **a column of buttons is added for data entry** while holding the scientific mode buttons. With this data it is possible to perform the following operations.

- Indicate the amount of data entered.
- Add the data entered.
- Calculate the average of the data entered.
- Add the square of all the data entered.
- Show the median of the data entered.
- Calculate the standard deviation or the typical population.

#### Numbering system mode

With this mode we can **perform calculations in decimal, binary, hexadecimal and octal systems.**

I am the first to recognize that the calculator is not a topic that will catapult us to the top places or bring us millions of visits. But, in addition to the aforementioned reason of paying tribute to the developers behind it, it is a good excuse to learn about the usage habits of other Linux users.

Do you use the calculator on your desk? If you want, tell us in the comments form.