Absolute cell reference formula help

[johnny5]

I have a spreadsheet that calculates count and sales by item for a 12 month rolling period. I've been updating the formula everytime I add or delete a month to create a new 12 month period. I need a formula to sum the same cell references for each item and not be affected by the addition or deletion of columns. I tried the INDIRECT function but I cannot figure out the correct syntax because I am not using a constant range. Any help would be appreciated.

Book1
	A	B	C	D	E	F	G	H	I	J	K	L	M
1	Item	Jan-05	Jan-05	Feb-05	Feb-05	Mar-05	Mar-05	Apr-05	Apr-05	May-05	May-05	TTL	TTL
2	Num	Count	Sales	Count	Sales	Count	Sales	Count	Sales	Count	Sales	Count	Sales
3	MX-123	223	$8,920.00	193	$7,720.00	273	$10,920.00	217	$8,680.00	225	$9,000.00
4	TL-500	117	$4,680.00	86	$3,440.00	115	$4,600.00	125	$5,000.00	111	$4,440.00
5	ES-445	441	$17,640.00	413	$16,520.00	462	$18,480.00	380	$15,200.00	290	$11,600.00
6	MT-600	621	$24,840.00	561	$22,440.00	600	$24,000.00	580	$23,200.00	582	$23,280.00
Sheet1

 

[want2b]

The absolute cell reference won't work?
You probably blew right past me but
I would think that =$C$3 in cell AC3 would equal $8920
until you deleted colums C and D then it
would equal $7720 in cell AA3
probably missed your point

 

[joelnichols]

Would something like this work?

Book12
	A	B	C	D	E	F	G	H	I	J	K	L	M
2	Part	Count	Sales
3	TL-500	554	22120	117	4680	86	3440	115	4600	125	5000	111	4400
Sheet1

In B3 =SUM(INDEX(3:3,,4))+SUM(INDEX(3:3,,6))+SUM(INDEX(3:3,,8))+SUM(INDEX(3:3,,10))+SUM(INDEX(3:3,,12))

In B4 =SUM(INDEX(3:3,,5))+SUM(INDEX(3:3,,7))+SUM(INDEX(3:3,,9))+SUM(INDEX(3:3,,11))+SUM(INDEX(3:3,,13))

Ugly and probably not the best way to do this but...

 

[joelnichols]

Got it looking a little better here



=SUM(INDEX(3:3,,4),INDEX(3:3,,6),INDEX(3:3,,8),INDEX(3:3,,10),INDEX(3:3,,12))

 

[johnny5]

Sum / Index works great for this application.
Thanks for your help.