If you mean you want to enter this in, say, cell X99 and have i
display this way in X99, you'll need to use a Change event handle
macro. Do you want to be able to calculate using this entry as well? I
so, that Change event handler would need to create and use a custo
number format to do so.
For starters, here's a link to a udf that would generate the neede
text.