How can I convert numbers formatted as text back to numbers?

[Living_Fossil]

Version: 2008
Operating System: Mac OS X 10.5 (Leopard)
Processor: Power PC

I have downloaded a set of very large tables from a UK Government source, and it turns out that most of the numbers shown are formatted as text. In Excel 2008, when such a cell is selected it is marked with a little triangle, and a warning shows up next to the cell, with a drop-down list explaining that the number is formatted as text, and there is line you can click on within the list to turn the text back into a number. But I have thousands of such numbers, and I can't see a function or any other way of turning them all back into numbers via a formula. Can't find anything in Help. Can anyone help me?

 

[Niek Otten]

Copy an empty cell. Select your data and Paste Special, choose Add operation

 

[Living_Fossil]

Thanks - that did it! The only thing that didn't work was the occasional cell that contained a genuine non-number (a letter): this technique produced an empty cell instead of the letter - but I think I can find a workaround for that.