To round all numbers to nearest 10:

Select tools calculation Precision as displayed then format cells
number custom "#,.00".

(Switch ",." to ".," for European settings). It's probably best to copy
data to a new workbook first and then paste back as formulas only.

To subtract 1 from cells:

Enter 1 in a cell copy, edit goto special constants numbers and
Edit paste Special Values and Subtract.

mateo wrote:

Hi, I have worksheet full of prices that I want to round to the nearest
multiple of 10 then subtract 1 to get a nice price with 9 on the end. (having
already multiplied the original numbers by a percent to change currencies)

I know how to make $47 into $49 by using =mround(47,10)-1 but how do I
apply it to the whole sheet? Paste special Formulas is not working for me...

Thanks