There is another alternative to the ribbon command Insert (or Mailings) | Field 
| Calculation presented in the last sections: the keyboard command F8.
The difference:
The ribbon command Insert (or Mailings) | Field | Calculation is suitable for any complex calculations with variables, etc.
The keyboard command F8 is only suitable for simpler calculations, but it is much easier to use: You simply type a formula directly into the text, select it and press the F8 key – the result is already in the text.
An example:
| 1. | Type: "The sum is: 90+55+220". |
| 2. | Select "90+55+220". |
| 3. | Press the F8 key. |
| 4. | The formula "90+55+220" is now calculated, and the result is inserted into the text. |
Tip: As an alternative to pressing the F8 key, you can also right-click on the selected formula "90+55+220" to open the context menu and select the menu item at the bottom: Replace with result "365".
Important: In contrast to calculating with the ribbon command Insert | Field | Calculation, the result is not created as a field with the F8 key or via the context menu here but is written into the document in plain text.
Order of operations: The order of operations rule applies, i.e., multiplication and division before addition and subtraction. Multiplication and division operators take precedence over addition and subtraction operators, thus multiplication and division are performed before addition and subtraction. Thus, 2+3*4 equals 14. The order of operations can be modified by parentheses: (2+3)*4 equals 20.
Using functions: Not only the basic arithmetic operations are allowed but also functions (see Formulas and functions): Type "SQRT(2)", select it and press the F8 key to display the root of 2.
One line limit: The selected calculation must be within one line of text. If you select several lines of text, the F8 keyboard command is not available. In this case, use the ribbon command Insert | Field | Calculation.
Summing the contents of table cells
Such calculations can also be performed in tables. There is yet another function here:
▪If you have selected a calculation within a table cell, you can calculate it as described above using the F8 keyboard command.
▪If you select several entire table cells, TextMaker uses the F8 keyboard command to calculate the sum of the values in the selected table cells. A window then appears and indicates the result. If you simply want to take note of this and no longer use it, click on Close. Alternatively, you can select the Copy button. TextMaker then copies the result of the calculation to the clipboard. You can now insert the value at any position in the document using the ribbon command Home | Paste.
Tip: Adding the "Evaluate" button to the ribbon
For convenient access, you can also add the command Evaluate 
as a separate button on a ribbon tab. If you use this command, it does exactly the same as the F8 keyboard command.
To do so, choose the ribbon command File | Customize | Customize ribbon to open the dialog box for customizing the user interface, and search there for the command "Evaluate". Then proceed as described in Customizing icons and groups in the ribbon.
Note: The "hamburger menu" 
can be used to access the "Evaluate" command directly by default as in the classic menu interface with the menu command Edit > Evaluate.