Pete_UK wrote...
Those numbers you have exported/imported could still be text -
changing the format (of the cell) will not change their value. A quick
way to change them is to highlight the numbers then click on Data |
Text-to-columns and then click Finish on the first panel.
....

If the source data comes from HTML tables, it likely includes
nonbreaking spaces. Text to Columns doesn't remove nonbreaking spaces.