Abstract thinking is sadly lacking from our school curriculums. I've seen students even at university level who are bewildered by equations like w^2-2w+4=0 or

Abstract thinking is sadly lacking from our school curriculums. I've seen students even at university level who are bewildered by equations like w^2-2w+4=0 or d/dm(m^3-m^2+m) just because the they haven't been taught that the variable x is just an abstraction.