A formula cannot delete/add/copy etc; it can only display a result
In the first cell in column next to the one of interest enter
=--(mod(row(),10)=1)
Copy this down as far as needed
This will give you a series of zeros and ones (0, 1) with every tenth row
having the 1 value
Next we must turn these formulas to values so we can sort: select all the
new cells; use Copy and with them still selected use Edit |Paste Special and
specify values
Sort the two column (the one of interest and the new one) with the new
column as the sort key
Now all the 1's are at the bottom and can be deleted
Then delete the new column
best wishes
