I know there are a lot of questions here; answer them at your convenience folks. And if I discover the answers, I will post back as well.

These questions will help me understand the logic a lot better. (And yes, I am continually reading xld's step-by-steps, but I am sometimes too dumb too even follow it )

Alright. I have searched and searched. The excel help file is silly.

All I want to do is confirm that when we use two Multidimensional Arrays in SUMPRODUCT the order of operations is indeed what I belive it is.

Question 1: Is the following correct?

By playing around with it, it seems that if I use two 2 x 2 Arrays as my arguments, then SUMPRODUCT(Array1, Array2) will do the following:

Multiply corresponding elements of each array, which would, in theory, yield another 2 x 2 Array. And then it SUMS all of the elements of the resultant Array.

For example:

Given two 2 x 2 Arrays

A = {a, b ; c , d}

B = {w, x ; y, z}

Then SUMPRODUCT(A , B) = (a*w) + (b*x) + (c*y) + (d*z)

I know it's a stupid question, but I keep getting confused with Matrix Multiplication which returns an Array (as opposed to a Scalar).

Question 2:

DO we ever use Ctl + Shift +Enter with SUMPRODUCT? [I don't think we do..but I am not positive]

Question 3:

What happens when we do not use Ctl + Shift + Enter with MMULT() ? [I am under the impression that it will just return ONE element of the resultant Array]

Question 4:

By ANDing (i.e. using '*') You can SUMPRODUCT two Arrays of unequal Row-length so long as they

have the same Column-Length....right?

For Example:

[vba]

SUMPRODUCT((A1:A4)*(B1:C4))

[/vba]

is EQUAL TO

[vba]SUMPRODUCT(A1:A4, B1:B4) + SUMPRODUCT(A1:A4, C1:C4)[/vba]

correct?

Question 5:

Can all of the SUMPRODUCT 'tricks' be applied to VBA SUMPRODUCT?