"When an implementation does not support a formula syntax, typically the values are shown when office:value is present, but formulas themselves are removed. A simple example is a SUM function that calculates the sum of 2 cells. When opening a spreadsheet, a user may not notice any difference because the values are still there. But when changing the values of these 2 cells, the value of the cell originally containing the SUM function will not be updated accordingly because the formula has been removed."