Updating Info from a previous worksheet
 

I have a worksheet that shows "mileage" such as 999999 and I will manually
update on a new worksheet todays mileage #, I have a space commited to show
the amount of "miles" traveled in the 2 day span. (that parts all good). ow
my problem is that I need it to update the place it is going to pull the #
from (previous days worksheet) how do I do that so it pulls from the previous
worksheet automatically? Here is what the formula looks like: =H8-'7-31 &
8-1'!H8 then for the next worksheet I need it to look like this: =H8-'8-2 &
8-3'!H8

Any help is apreciated.. is this even possible?
Thanks!