What's the equivalent of this degree in Europe and USA? I'm an undergraduate student in mathematics at the University of Buenos Aires. The name of the degree is "licenciatura en Matemática", which is a 5 year long degree. To graduate you must make a small work called "thesis".
Now while the degree is about mathematics, you can choose between two orientations, in the third year: pure and applied. 

If you understand spanish: http://cms.dm.uba.ar/academico/carreras/licenciatura/
The University of Cambridge's International Qualifications page recognizes a "Licenciado with an overall grade of between 8 and 9 out of 10" as "At least a 2i honours degree from a UK university or an equivalent standard from an overseas university", but also says that it's equivalent to a Singaporean Master's degree. I'd guess that most universities would consider it definitely equivalent to a Bachelors and probably also a Masters degree.