How to avoid N.aN?

In my grid, I have a formula in a column like this:

So, whenever a new row is added, till the values in the columns 1 & 2 are entered, the value in the last column is shown as N.aN. This is understandable as it is not a number. But is there a way that we can avoid showing N.aN & display nothing in that case.

In short, I want to show nothing (blank) in case of N.aN

Thanks in advance.

Try to set an empty value for all cells of a needed row right after it’s adding.
For example:

//execute code for each cell in row with id “row1”
//cellObj - related cell object
//ind - column index