I have to change a great amout of formulae from a simple

=A3/A4 to either

=ROUND(A3/A4,0) or

=IF(A4=0,"",A3/A4)

The cells are spread all over the sheet, sometimes in one row or line,
sometimes grouped together or sometimes individually placed anywhere on the
sheet.

Is there an easy way to change these formulae faster then individually
change each cell? Even changing each cell individually would be easier if
there was a way to wrap the old formula between the necessary alteration.

(PS: ASAP has a Macro that can alter the formula, but it can only add
something at the end and the formula is lost and the new value is shown.)