Have you ever pasted a number into Excel and watched it turn into something like this:
That's not terribly useful if you're storing a product ID or tracking number in a spreadsheet. Worse, it changes the number itself if it exceeds 15 characters. 123456789012345678 becomes 123456789012345000; the last three numbers are zero'd out!
If you're not doing math with these numbers, there is a way to preserve the exact value and force it to display without the scientific notation. Before you paste any long numbers, select the cell(s), right-click, click Format Cells and choose Text. That's all there is to it.