I tried 0.1 + 0.2 in both google docs and excel. I got 0.3000000000000000000, not 0.30000000000000004, like you normally would using floating point.
Excel definitely used floating point in the past (because you used to be able to use it to test for the Pentium FDIV bug) and according to the documentation, it still does: https://support.microsoft.com/en-us/kb/78113