XLC has some special functions to control what is displayed above and below a division line in an equation.

Notes

The OVD() function places everything inside of the brackets over the division line. A division character "/" must immediately follow the closing bracket of an OVD() function. An OVD() function is always followed by a UND() function.

The UND() function places everything inside of the brackets under the division line. A division character "/" must be immediately before a UND() function. An UND() function is always preceded by a OVD() function.

Failure to position the functions in this order OVD()/UND() will result in the following error "#OVD()/UND() function misuse. Check that OVD() occurs immediately before / and UND() occurs immediately after /.#"

OVD()/UND() functions cannot be nested. 

German Version of Excel

UND() is used as the logical AND() function in German versions of MS Excel. To prevent conflicts:

    UDI() can be optionally used in place of UND().

    and for the sake of consistency ODI() can be optionally used in place of OVD().