I want to take A1:A10 and multiply by .585
then...
A:11:A20 multiplied by .55
= total result on A25

I went something like this....and it won't work:
=sum(a1:a5)*.585+(a11:a20)*.55

All I get is #VALUE and the help prompts do not help.
I am using Excel 2007

Any help appreciated