External and Internal representation of formula 

Internal formula representation - is how it presence in the file. External representation - is how user see the formula at screen.

Conversion between External and Internal representation is not obvious (it depends on local language and other parameters).

Because of it, you should pass internal representation of formula into your Context. Below is how to determine it:

• • • Create empty Excel-document and write required formula into some cell :

• • • open found file  sheet1.xml   with any XML-editor, and there see internal representation of your formula:   

• • • don`t forget add = (equality) sign to begin of formula. I.e. finally you should pass such formula into Context:

=SUM(U5,V5)

Formula reference styles

You can use both of A1 and R1C1 notations:

• • R1C1 style example:  =SUM(RC[-3],RC[-2],RC[-1]) 

  • A1 style example:      =SUM(B4,C4,D4)