Why is the title "vba help..."? Your examples are Excel formulas.
Fluff already explained the major issue: add, instead of subtract.
But I wonder if you also need to explicitly round in order to avoid infinitesimal differences of the form 9.09E-13.
(We are probably unable to duplicate the rounding problem because XL2BB does not provide the exact binary values in column A and column B, which I assume are calculations in the actual Excel file.)
And yes, VBA and Excel results might differ in that respect, in part because of "tricks" that Excel plays.
In Excel, write:
=ROUND(A2+B2, 2)
In VBA, write:
Range("C2") = WorksheetFunction.Round(Range("A2") + Range("B2"), 2)
FYI, I use WorksheetFunction.Round instead of VBA Round because the latter rounds differently ("banker's rounding"). It might not make any difference in this case. But I eschew the use of VBA Round on principle.