Formula to prevent the duplicated value

[Mohammednt0]

as you can see we just finished balance for month 8,

but the formula is duplicating the month 8 (534360) value !

is there a way to return "-" instead of the duplicated month 8 value?

I use this formula =E21-L21+N19

please check the attached file

[HansV]

Change the formula in M11 to

=IF(K11=0,0,E11-K11+M9)

Then copy to M13, M15, etc.

[Mohammednt0]

thanks it worked