Excel Help (No doubt it's a simple fix)

[lego]

I'm trying to set up an inventory file. What I need is for the product number to sequentially change for me, I thought this would be easy (autofill) but as the product number contains letters it does not want to play.

Essentially what I'm looking for is this

ITM-0001
ITM-0001-Small
ITM-0001-Medium
ITM-0001-Large
ITM-0001-XL
ITM-0002
ITM-0002-Small
ITM-0002-Medium
ITM-0002-Large
ITM-0002-XL
ITM-0003
ITM-0003-Small
ITM-0003-Medium
ITM-0003-Large
ITM-0003-XL

.... Down to 380.

Can someone help?

 

[lego]

Best bet is probably to create a column which contains the numbers, then in the product number column use a formula to concatenate the number with the rest of the product no

Problem I'm running into here is when I create the sequential numbers I'm using 0001, 0002, when using the forumla it converts them back to 1, 2 ect

 

[lego]

Treat it as text not a number. Excel will still add 1 when you copy paste down.

Excel won't seqentially fill the numbers is listed as text