If you encounter multiple hash tags "####" being displayed in any cell, it usually means the text/numbers are too large to be displayed within the column width.
Click the cell, Menu -> Home -> Wrap Text -> Shrink Text to Fit
- Zoom in (the numbers may be too small to display, if you are zoomed out too much) or;
- Reduce the font-size or;
- Make the column width wider by clicking and dragging the right edge of the column or right clicking the top column letter and adjusting column width from there or;