LibreOffice 7.5 Help
Specify the settings for up to three subtotal groups. Each tab has the same layout.
Select the column that you want to control the subtotal calculation process. If the contents of the selected column change, the subtotals are automatically recalculated.
Select the column(s) containing the values that you want to subtotal.
Select the mathematical function that you want to use to calculate the subtotals.