Track From 3 to 3/37

I've been making my own compilations and was curious if there was a way to modify the tags. I appropriately rename the file itself and was wondering if an expression/something existed to help me do the following.

I would like to take the original track number from the file name (ie:3) and then add that on the total number of tracks (that I could specify myself, ie: 37) so that the track number in the tag would show as 3/37.

Any ideas how this could be accomplished? Any help would be appreciated.

Edit: Of course, minutes after I post this I find the answer in the auto-numbering wizard. Thank you for this option.