What works like Lotus semi colon?

I used the semi colon in Lotus to retain old #'s in cells or to keep notes in certain cells. I know I can use comments in excel to keep notes for cells, but I would like to know if excel has a way to simply separate a new number from an old number within the context of the cell and not have to retype the old number into the comment field. In Lotus all you did was type: 123; 456 this is the old number. Only the 123 showed up but if you looked in the cell, you could see both numbers and the text information.