Numbers can coexist in Excel cells with text strings. What may surprise you is that the contents of such cells can be treated and used as numbers. It means that they can be used as ordinary numbers in mathematical calculations, functions and formulas. This happens when you apply some kinds of custom formatting for cells.
Here is such example of cell formatting and some confusing results of using it in formulas involving text strings.
I've used the following custom format for cells in column A: