**Question description:**

*This user has given permission to use the problem statement for this blog.*

I need a formula for the sum of row a1-a500 where its a1*a2 + a3*4 + a5 * a6... etc

Solved by C. E. in 20 mins

This is the chat thread from the real Excelchat help session. It contains no private user information.

Excelchat Expert
30/05/2018 - 02:21

HI

User
30/05/2018 - 02:21

hello

Excelchat Expert
30/05/2018 - 02:21

Hope you are doing well today!

Excelchat Expert
30/05/2018 - 02:21

Welcome to got it pro!

User
30/05/2018 - 02:22

i just need a quick formula

User
30/05/2018 - 02:22

:)

Excelchat Expert
30/05/2018 - 02:22

OK

Excelchat Expert
30/05/2018 - 02:22

I saw your request

Excelchat Expert
30/05/2018 - 02:22

Pleases give me some time and see how it will work

Excelchat Expert
30/05/2018 - 02:22

1

User
30/05/2018 - 02:24

ill manually do an example on column g so u can see

Excelchat Expert
30/05/2018 - 02:24

Sure

Excelchat Expert
30/05/2018 - 02:25

Ok. I see

Excelchat Expert
30/05/2018 - 02:25

Is there certain math formula associate with this?

Excelchat Expert
30/05/2018 - 02:25

Or not really?

User
30/05/2018 - 02:25

no math formula

User
30/05/2018 - 02:25

just need a structure

User
30/05/2018 - 02:26

just need a formula for the cell number G8

Excelchat Expert
30/05/2018 - 02:26

Is there anyway, you can split the odd and even row into 2 seperate columns?

User
30/05/2018 - 02:26

so it calculates the sum of stuff before it

Excelchat Expert
30/05/2018 - 02:26

Sure. I see what you are trying to do

User
30/05/2018 - 02:26

ummm our current excel is daily columns, splitting into two would be a significant delay

User
30/05/2018 - 02:26

and lots of manual work

Excelchat Expert
30/05/2018 - 02:27

Yes. Thats true

User
30/05/2018 - 02:28

and we currently have over 2000 rows for each column

User
30/05/2018 - 02:28

so manually inputting a1*a2 + a3*a4 is going to take too long

Excelchat Expert
30/05/2018 - 02:28

Sure.

Excelchat Expert
30/05/2018 - 02:28

Please allow me couple of minutes to try something

Excelchat Expert
30/05/2018 - 02:29

Are you allow to split the column??

Excelchat Expert
30/05/2018 - 02:29

If yes, then there is a way to do it

Excelchat Expert
30/05/2018 - 02:29

=mod(A1,2)

User
30/05/2018 - 02:29

split columns?

Excelchat Expert
30/05/2018 - 02:29

For all the numbers in column A

Excelchat Expert
30/05/2018 - 02:30

we are calculating the reminder at this point

Excelchat Expert
30/05/2018 - 02:30

so, it will show either 1 or 0

User
30/05/2018 - 02:31

no i dont think we can split into two columns for now

Excelchat Expert
30/05/2018 - 02:32

Then, it may not possible to do so

User
30/05/2018 - 02:32

we had this forumla before

User
30/05/2018 - 02:32

for calculating only the odd numbered cells

User
30/05/2018 - 02:32

=ArrayFormula(SUM(IF(MOD(ROW($B$2:$B$500),2)=0,$B$2:$B$500,0)))

User
30/05/2018 - 02:32

is there anyway to modify it

User
30/05/2018 - 02:33

so that its a1:a2, a3:a4 etc?

Excelchat Expert
30/05/2018 - 02:33

Please allow me to take a look

Excelchat Expert
30/05/2018 - 02:39

Well, I think this formula is good to use if you are not considering A1*A2+A3*A4+ etc.....

Excelchat Expert
30/05/2018 - 02:39

If you need very specific cell do multiply then do the sum, I think this formula may not work

Excelchat Expert
30/05/2018 - 02:40

Unless you allow to seperate 1 column into multiple, then this problem will be easier

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