Zeromeracy
When someone is at home with the oft-counterintuitive properties or numerical idiosyncrasies of the number zero—for example, although zero is neither positive nor negative, it behaves like an “even number.”
To appreciate the power and beauty of Calculus, one must be able to understand zero and to learn to live with it, because if zero is let loose, one can only expect chaos from the numerical troublemaker—one needs to be versed in zeromeracy to tame the “infidel number.”