sum numbers only when a named cell is not zero

[Guest]

In my spreadsheet, I need cell L10 to sum cells ( M10-P10) if P10 does not
equal zero. P10 is a formula=+n10+O10.

 

[Bryan Hessey]

Cheryl,

try

=if($P$10<>0,sum(M1010),"")

or

=if($P$10<>0,sum(M1010),0)

to reflect a zero.

 

[JE McGimpsey]

One way:

=IF(P10<>0,SUM(M1010),"")

Given P10's formula, it could also be

=IF(P10<>0, 2*P10+M10,"")

or, if you want to return 0 instead of a null string:

=(P10<>0)*(2*P10+M10)


Note that the first "+" in your formula is superfluous.