Instead of typing each month in successive cells, you can use Autofill to quickly add the months of the year to a Numbers table.
To add months using Autofill:
Want to populate a table row or column with the days of the week? Just type “Sunday” into the cell and follow the same three steps.
Can Numbers do the same for numerical series? Absolutely.
To add a numerical series using Autofill:
Since you incremented the values in the selected cells by 5, Numbers also fills successive cells with increments of 5.