More elegant way

[Tasss]

Hi.
I want Excel to execute the following:
=SUM((I5*C5),(I6*C6),(I7*C7),(I8*C8),(I9*C9),(I10*C10),(I11*C11),(I12*C12),(I13*C13),(I14*C14),(I15*C15),(I16*C16),(I17*C17),(I18*C18),(I19*C19),(I20*C20),(I21*C21),(I22*C22),(I23*C23),(I24*C24),(I25*C25),(I26*C26),(I27*C27),(I28*C28),(I29*C29),(I30*C30),(I31*C31),(I32*C32),(I33*C33),(I34*C34),(I35*C35),(I36*C36),(I37*C37),(I38*C38),(I39*C39))

Now, this works perfectly well, but is, as you can imagine a bit of a pain to enter. I am sure there is a more elegant way but can't think of one right now. Could anyone help, please?

Thanks a lot.

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[steve the fish]

Excel has a function for this called SUMPRODUCT.

 

[Tasss]

Life can be so simple if you know how...

Thanks!