I am trying to run a spreadsheet of daily calculations and I am having
trouble setting up the formulas. Here is an example of what I am trying to
do:

date reading usage
A B C
1 12345 11111
2 23456 11111
3 34567
4
31 56789
Then I am wanting to take the number that I put in the 1st for the new
month, to subtract the 31st to get the usage for that day.My delema is that I
can't figure out how to set up the formula to subtract the last day of the
month from the first of the next month. Since some months have 31 days, some
with 30, and the dreaded 28 of February.

I am sorry about the naivity, but I am new to this, so please bear with me.

What I would like to do is subtract the last day of the month from the first
of the new month. Can I do that on the same spreadsheet, or will I have to
use a different one? If so, how do I switch to a new sheet?

Thank you for any help.