Having been a teacher, I can say that about 50% of what you are taught in school becomes wrong at some point.
Maths is usually OK, but some genius at some point will question even that.
History depends on who's telling it. Different countries, and even regions, tell it from their own point of view.
Geography is always changing even if it's only outlines of countries through coastal erosion.
English is a living language and therefore changes as new words and ways of communicating develop.
The sciences most definitely change as new discoveries are made. For instance, when I was at school in the 1950s who knew that mercury gives off dangerous vapour? And how many of us happily sucked on asbestos fibres when using Rawlplastic for holding screws into walls?
So really a fact may only be a fact depending who's telling it, when it's being told, when it's proven to be completely wrong or until something else supercedes it.