We don't have issue with the math, we just disagree on what to fund to balance things out.
An example, 200+ billion euros are given yearly to large companies as tax breaks and the like, without the government asking anything in return. The senate had a report about it recently [https://www.publicsenat.fr/actualites/economie/un-cout-annue...].
Another example, the military and defense get a huge increase in budget. schools, hospitals, research, nearly every public service get a budget cut instead [ https://www.force-ouvriere.fr/non-aux-44-milliards-d-economi...].