There must be a simple answer. The pound symbols in a cell indicate that the field is not wide enough to show the full value. The best solution is to highlight all the column headings and double-click on the right edge of the last cell. All the pound signs will disappear. Better yet, each column will resize itself to accommodate the largest data in any cell.
Columns can either expand or shrink.
This is beneficial as you will have the maximum number of legible columns on your screen. You could also just change a single column by double-clicking the right divider of the column heading. As you point with the mouse, your cursor should mutate into a double-headed arrow. The pound symbol had the same meaning in Lotus. Let me make a further point.