A lot of university have requirements like ;GCSE Minimum 6B in GCSE MathematicsWhat does it mean Is it taking at least 6 subjects with B

The requirement "GCSE Minimum 6/B in GCSE Mathematics" means that in order to be eligible for admission to the university, you must have obtained a minimum grade of B in GCSE Mathematics.

It does not refer to the number of subjects you need to take, but rather your performance in Mathematics specifically. So, regardless of the number of subjects you have taken, you need to have achieved at least a B grade in GCSE Mathematics.