Numbering on spreadsheet not working like exel

Numbering on spreadsheet not working like exel

I am trying to renumber a column from sporadic numbers to a sequential set.  1, 2, 3, 4 etc.  When I highlight then all and go to the bottom right corner, like on excel and when I drag it down to fill, it sets everything to the first number I selected.  So from in this example, it does NOT go to 1 2 3 4 5 6 7 8 etc, it turns everything to 1 1 1 1 1 1 1 1   What's going on here?  I have A LOT of numbering to do and this will get very cumbersome. 

Thanks