Enter this formula in your "food cell" :

=IF(B12="","",100)

The food cell will remain blank until you enter something in cell B12. I'm
assuming that all you'll enter into cell B12 is a number.

--
Biff
Microsoft Excel MVP


"Fernandokim" wrote in message
...
i'm trying to build a budget and i need help.........can someone tell me
how
can i put a fix number into a cell of a number that i don;t know yet....
for
example
I want to allocate 100 into food out of my income cell (B12), but because
my
income change week to week i will not know how much it is until pay
day........so what i want to put in the food cell is...."100 of B12, so
whenever i put the amount on B12 cell 100 will go to food cell