"Bob Phillips" wrote...
Even rows: =SUMPRODUCT(--(MOD(ROW(B1:B30),2)=0),B1:B30)
Odd rows; =SUMPRODUCT(--(MOD(ROW(B1:B30),2)=1),B1:B30)

Yes, but if you had the sum of even rows in, say, X99, then it'd be more
efficient to calculate the sum of odd rows using

=SUM(B1:B30)-X99