# About calculations

By creating calculations, you add new columns to your dataset. These new columns are based on existing columns from your data source. The calculations are available for all the visualizations that are based on your dataset.

Your data source contains the following columns:

- Total Revenues
- Total Expenses

For your data analysis, you need to see the trend of the net income. The Net Income column does not exist in your dataset, so you need to create it as the difference between total revenues and total expenses:

*Net Income = Total Revenues - Total Expenses*

The corresponding calculation has the following form:

[Total Revenues] - [Total Expenses]

Your data source contains the following columns:

- City
- Country

In the visualizations, on an axis, you need to show both the cities and the corresponding countries, in the following format: *city, country*. For this, you need to create a column named City and Country, where the city and the corresponding country are separated by a comma. The calculation for the new column has the following form:

[City] + ', ' + [Country]

You have several options for adding a calculation to a dataset:

- Type the calculation.
- Use a predefined function.
- Use a script. For details about script calculations and connections to AI/ML servers, see Data science capabilities.

The following topics present detailed information on adding and managing calculations: