Adding multiple rows/columns to a spreadsheet in LibreOffice Calc

Inserting more than one row/column at a time

• To insert multiple rows into a Calc spreadsheet at one time, select the same number of rows as you want to add, beginning at the row AFTER where you want the insertion to be, then
  • Ctrl-click/right-click on the row header (where the row numbers are) within your selection, and choose Insert Rows from the contextual menu, or
  • Click on the “Insert Rows” button in your toolbar (if it’s visible there), or
  • Choose Rows from the Insert menu.

• To insert multiple columns, just follow the above instructions subtituting ‘columns’ for ‘rows’ – it works exactly the same way.

Source: http://neowiki.neooffice.org/index.php/Adding_multiple_rows/columns_to_a_spreadsheet_in_Calc