Sum every third column in a row

[Carl B]

Is there a nifty formula that would allow me to sum every third cell in a range?

 

[PaddyD]

which range? starting at which cell in the range?

Paddy

 

[Carl B]

C10:C67

 

[Tom Urtis]

See if this does it; thanks to Aladin for assisting:

=SUMPRODUCT((C10:C67)*(MOD(ROW(C10:C67)-ROW(C10),3)=0))

 

[Carl B]

Thank you Tom and Aladdin,
I kind of mislead you in the range that I was looking for, it should of been something along the lines of C10:AL10. Very intersting formula, I believe I can modify it to work for me. Thanks again for pointing me in the right direction.

 

[Carl B]

Thanks again, I changed ROW to COLUMN and it works perfectly!

 

[Aladin Akyurek]

On 2002-09-26 20:56, Carl B wrote:
C10:C67

=SUMPRODUCT((MOD(ROW(C10:C67)-CELL("Row",$C10)+H1,H2)=0)*(C10:C67))

where H1 houses the index that indicates the value to start with from the set of values of interest and H2 the index that indicates the Nth value to sum.

If you want to sum beginning with the first value, set H1 to 0. Since you want to sum every 3rd value, set H2 to 3.

Tom Urtis/Juan Pablo: This formula in fact reduces 4 different formulas to just one with 2 parameters (see Pearson's SUMEVERY.XLS). It's independent of the native row/column number. I remember attempting such a formula at the old board in an exchange with Juan but failed to succeed. I had promised myself to dedicate such a formula to Juan if I could build it.

Aladin

 

[Aladin Akyurek]

On 2002-09-26 21:46, Carl B wrote:
Thanks again, I changed ROW to COLUMN and it works perfectly!

It won't if you insert columns before your data... Use instead:

=SUMPRODUCT((MOD(COLUMN(C10:AL10)-CELL("Col",$C10)+H1,H2)=0)*(C10:AL10))

See my other post in this thread for H1 and H2 (which I suppose to be 0 and 3 respectively in your case).

Aladin
This message was edited by Aladin Akyurek on 2002-09-26 22:01

 

[Tom Urtis]

Thanks again Aladin.

 

[Myproblem]

hi guys, i am new here

i have problem with summing every 7th number in 10 digit number, like this:

A B
1000004000 100
1000005000 50
...
...

i have in column A like above number with 10 digit number, and in column B specific values.
i need formula, it would be great just one to sum all values in column B but with criteria that formula summin every 7th, example 7th number is 4; number in number in column A

thx