Monthly Date Increase in Calc

To increase the date by a month in a series in LibreOffice's Calc spreadsheet program there are different options depending on the particular date that is to be increased.

To increment most dates  (e.g. January 12, 2000; February 12, 2000; March 12, 2000; etc.)

1. Input the first date in the series in a cell, for example cell A1
2. In the cell underneath it (i.e. cell B1) input the following formula referencing the cell above: =DATE(YEAR(A1),MONTH(A1)+1,DAY(A1))
3. Click on the cell with the formula and then drag the bottom left corner handle down to fill the column with monthly incremented dates

To increase dates at the end of the month (e.g.  January 31, 2000; February 29, 2000; March 31, 2000) a little more finesse is required. Follow the above procedure but change the formula to the following:

=DATE(YEAR(A1),MONTH(A1)+2,0)

To better understanding what is going on:
 =DATE(YEAR(A1),MONTH(A1),0) ends up referring to the last day of the previous month
 =DATE(YEAR(A1),MONTH(A1)+1,0) ends up referring to the last day of the current month
 =DATE(YEAR(A1),MONTH(A1)+2,0) ends up referring to the last day of the next month

Insert Multiple Rows in Calc or Excel

Inserting Rows in Calc or Excel Spreadsheet

To insert multiple blank rows in LibreOffice's spreadsheet program Calc, immediately underneath the point where you wish to insert the rows use shift-click to select the number of rows you wish to insert, whether they have content or not, and then right-click on the numbered column on the far left and select Insert Rows Above.

To insert even more rows, using the repeat/redo keyboard shortcut Ctrl+Y may be helpful.