What is vuj calculus?

I have not heard of 'vuj calculus' before. I think you maybe mean 'vuja de'. The sound is very close. This is not a maths thing. It is an idea from psychology. It is like the opposite of déjà vu. It is when you see a familiar thing, but it feels completely new and you see it different.

Calculus is a hard type of maths about how things change. So, they are not the same idea. It is easy to mix them up. The names sound a bit alike. Hope this helps you.