=SUM((C31:C46)*(E31:E46))-SUM(...)/2+Sum(...) + Sum(...)

If you wish, you could use just one "Sum" function as in this Array formula.

=SUM(C31:C46*E31:E46,-(C47:C51*E47:E51)/2,C54:C59*E54:E59,C67:C71*E67:E71)

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HTH :)
Dana DeLouis


"Dave F" wrote in message
...
Here's the formula:
=SUM((C31:C46)*(E31:E46))-SUM((C47:C51)*(E47:E51)/2)+SUM((C54:C59)*(E54:E59))+SUM((C67:C71)*(E67:E71 ))

My guess is that these are matrices being multiplied together and matrix
algebra is different than straight multiplication. So, Excel requires
CTRL+SHIFT+ENTER to tell its calculation enginge to do matrix
multiplication....

Am I correct here?

Also: it seems to me that the same calculation can be done with
SUMPRODUCT.

Dave

--
Brevity is the soul of wit.