sum every nth cell in a row

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BNT1 - 21 Mar 2008 21:02 GMT

Sorry Posted in wrong group earlier

Hi

I am trying to adapt Bob Phillips formula

=SUMPRODUCT((B2:B32)*(MOD(ROW(B2:B32)-ROW(B2),n)+1=m))

I have cells, e5,e6,e7,e8,e9,e10,e11,e12,e13,e14,e15, etc
I want to sum, e5,e9,e13 etc
I will need to adapt this in another cell to add, e6,e10,e14 etc and
therefore need to understand the N + M value

I have entered the formula below in cell c5, but get 0. Have entered as
array formula
{=SUMPRODUCT((E5:AY5)*(MOD(ROW(E5:AY5)-ROW(B2),4)+1=F5))}

What am I doing wrong

Help appriciated

Brian

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T. Valko - 21 Mar 2008 21:48 GMT

>need to understand the N + M value

N = divisor used in the MOD function
M = mod

For example:

Using cell E5:

MOD(ROW(E5),n)=m

MOD(ROW(E5),4)=1

> I want to sum, e5,e9,e13 etc

=SUMPRODUCT(--(MOD(ROW(E5:E100),4)=1),E5:E100)

> I will need to adapt this in another cell to add, e6,e10,e14 etc

=SUMPRODUCT(--(MOD(ROW(E5:E100),4)=2),E5:E100)

Signature

Biff
Microsoft Excel MVP

> Sorry Posted in wrong group earlier
>
[quoted text clipped - 18 lines]
>
> Brian

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BNT1 - 21 Mar 2008 22:43 GMT

Keep getting #Value! error

copied and pasted in c5, and entered with shift+ctl+ent

>=SUMPRODUCT(--(MOD(ROW(E5:E100),4)=1),E5:E100)

Any ieas?

>>need to understand the N + M value
>
[quoted text clipped - 22 lines]
>>
>> Brian

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T. Valko - 21 Mar 2008 23:19 GMT

>entered with shift+ctl+ent

Doesn't need to be array entered but that won't cause an error. Just ENTER
will work.

> Keep getting #Value! error

Are there any #VALUE! errors already in the range?

Here's a small sample file that demonstrates this.

xSumNth.xls 14kb

http://cjoint.com/?dvxr6QVxsY

Signature

Biff
Microsoft Excel MVP

> Keep getting #Value! error
>
[quoted text clipped - 30 lines]
>>>
>>> Brian

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BNT1 - 22 Mar 2008 16:24 GMT

thanks T.Valko

After looking at the link, realised, I gave you wrong info, my range was in a
one row, different columns

changed "row" to "column" and presto worked !

Thanks for your patients

brian

Thanks fo

>>entered with shift+ctl+ent
>
[quoted text clipped - 16 lines]
>>>>
>>>> Brian

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T. Valko - 22 Mar 2008 17:52 GMT

Glad you got it straightened out. Thanks for the feedback!

Signature

Biff
Microsoft Excel MVP

> thanks T.Valko
>
[quoted text clipped - 29 lines]
>>>>>
>>>>> Brian

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