19.7. Formulas

Formulas are nested within columns (for iteration) or inside worksheets (for direct placement using the column and row attributes), and add calculations or functions to ranges of cells. They are essentially cells, see Section 19.6, “Cells” for available attributes. They can apply templates and have their own font definitions, etc., just as normal cells can.
The formula of the cell is placed in the value attribute as a normal Microsoft Excel notation. When doing cross-sheet formulas, the worksheets must exist before referencing a formula against them. The value is a string. 
 
<e:workbook> 
  <e:worksheet name="fooSheet"> 
    <e:cell column="0" row="0" value="1"/> 
  </e:worksheet> 
  <e:worksheet name="barSheet"> 
  <e:cell column="0" row="0" value="2"/> 
    <e:formula column="0" row="1" value="fooSheet!A1+barSheet1!A1"> 
      <e:font fontSize="12"/> 
    </e:formula> 
  </e:worksheet> 
</e:workbook>
This defines a formula in B2 summing cells A1 in worksheets FooSheet and BarSheet.