This is not an ordinary case for Excel. Strictly for Display purposes, you
can create the diagonal by doing Right-click > FormatCells > BorderTab > and
selecting the Diagonal Icon..........then you can enter your first value in
the cell normally, but before pressing enter, hold down the Alt key, then
press enter, then type in several spaces before finally typing in your
second value and then pressing Enter.........the cell should "appear" as
you want, but is virtually useless for performing further calculations
on.........
hth
Vaya con Dios,
Chuck, CABGx3