Totals are not too difficult. What may be more complex is as to why your Base “collapses” (probable a crash). You have not stated what version of LO you are using, where you got this from or the OS you are on.
For the totals look at my answer in this post → How to reuse an accumulated value in a Report?. You can create various detail totals, running totals and group or report totals.
Another post with a simple sample .odb → help with grand total.
Thank you for the sample. This is always a plus for solving problems.
The best way to solve your problem (and probably the easiest/cleanest way) is by basing the report on a query. The query can calculate the extend amount and the calculation is not needed in the report builder. You can then accumulate this field for totals.
SELECT "PRODUCT ", "QUANTITY", "PRICE ", "QUANTITY" * "PRICE " AS "LINETTL" FROM "Table1"
A note here. You were not too careful in designing the table. Notice
PRICE fields contain a space at the end. This makes it extremely difficult to work with (and find)!
The attached contains a revised version of your report. Notice the final total is on a Report footer and not a Page footer. Page footer is typically for page numbering and such. Totals on a Page footer don’t make much sense since a group can encompass multiple pages.
Revision of your sample: RevisedReport.odb
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