Need to create blank summation column

[Randy]

Hello everyone,

I need to create a column which will display the
multiplication of two previous columns with the stroke
(input) of one key. In other words, all other rows are
dependent on that one entry at the top. So normally,
until the variable is entered, the column would display a
bunch of zeros. I, however, want it to display an empty
field until such time the user enters in a number at the
top of the column. What command do I need for this?

Thanks!

 

[Don Guillett]

=if($c$1="","",yourformula)

 

[Ken Wright]

With your data in A2:A200 and B2:B200, in C1 put a 0, then select C2:C200, type =, then select
A2:A200, type *, select B2:B200, type *, select C1, then hit CTRL+SHIFT+ENTER at the same time to
array enter it. Formula will look like:-

=A2:A29*B2:B29*C1

Putting a 1 in C1 will instantly put all the values in the other cells.

If they put a 2 in however, the values would all be multiplied by 2, so if you didn't want that,
then amend the last part to (C1<>0) so that the formula now looks like:-

=A2:A29*B2:B29*(C1<>0)

If you'd rather not use an array, then in cell C2 put the following formula and copy down:-

=A2*B2*($C$1<>0)

 

[Randy]

Thank Don. And for "yourformula" should I use "isnumber"?
Someone told me that is the correct command.