Calculated columns are custom columns that you create (at design or run time) where the value is not in the underlying dataset but is dynamically derived from other cells in the row.
Create them with an Expression which can range from straightforward to very complex (we use Math.JS); they become a 'normal' column in your grid and update automatically as other values change.
This example we created 3 Calculated Columns: Avg Item Cost and Profit (which are numeric) and Comment (a string). Click the 5th button in toolbar to see details of the Expression - or 'Edit Expression' in the Column Header menu. Because they are treated as 'normal' columns we were able to include them in the layout we created (and we grouped on 'Comment') and also to style them (e.g. 'Profit') using Conditional Styles.