Custom function needed

[Viktor1]

Could somebody help me create a custom function that returns the following: A*SUM(A1:AN)+B*SUM(B1:BN)+C*SUM(C1:CN)+....+M*SUM(M1:MN) The variables would be A, A1, and MN. Many thanks!

A A1 A2 A3 ......AN
B B1 B2 B3 ......BN
C C1 C2 C3 ......CN
. . . . .
. . . . .
. . . . .
M M1 M2 M3 ......MN

 

[Kamolga]

What is A? B? C? is it row number?

 

[ZVI]

There is Excel function SUMPRODUCT for a such calculation.
Let's assume that M=4 and N=5 then do as follows:
1. Put coefficients A,B,C,D into the cells A1:A4
2. Put numbers into the cells B1:F4
3. Apply this formula to the cell L1: =SUMPRODUCT(A1:A4*B1:F4)

 

[Viktor1]

Thanks again! You saved me a lot of time.