Hello German,

The calculations are all different ways of finding the unique count of ID's when Tip Propiedad = 'Alquilada'

Modo1 and 4 are done with a filter and the Modo 2 and Modo 3 calculations have the filter built into the calc.

What are you trying to accomplish?  If you are new to Tableau, I suggest completing the online learning available Tableau Training and Tutorials 

Thanks

Patrick