I have a data table that calculates the averages of some data by month. Some months do not have certain averages and that is why the data table calculates them as div/0. I would like to leave those months, but change div/0 to "--". Since it is a data table, i cannot change anything there. So, i was trying to use a conditional formatting formula: ISERROR(A1), special format "--", but it doesn't work. I assume it doesn't, because the custom format works with numbers only. Is there any other way to do it?