I have a problem with the SUM() not calculating in a particular portion of a
spreadsheet. The spreadsheet is set up in sections where cells are being
summed within each section, then the sections sub-totals are being summed and
then those sub-totals are being summed up in a section at the bottom of the
sheet.

It appears that all the SUM() functions are working within the workbook
except for those in the final summary section at the bottom. In that
section, the first column where the functions were originally written is
working, but when the formulas are copied across to the left, they give a
result of "0". When clicking on the cells, the functions are copied
correctly, and I can see that there should be results in the cells, but I
cannot get these cells to give me a sum.