Hello all, I wonder if anyone can help me? Please?

I have a spreadsheet and its a month by month expense sheet for a local
club.

Problem is that when I try to add all the months total expenses, i.e.
January, February etc, the total of each month at the bottom of the sheet is
0.00.

I have checked all the formulae and the formula is correct, it relates to
each months totals, but returns a zero amount.

What is wrong?

Thank you
John