I am working with a spreadsheet with around 20,000 rows.

In a smaller spreadsheet, if I wanted to copy a formula down to the cells in the column below, I would simply drag and drop, or copy paste - easy..

Since this spreadsheet is so long, I'd like to be able to copy/drag the formula to all 20000 rows without manually scrolling down with the mouse button held down (as it takes ages)

Appreciate any suggestions for a shortcut.