According to Wikipedia, Kant's categories of the understanding are:

Quantity - Unity, Plurality, Totality.
Quality - Reality, Negation, Limitation.
Relation - Inherence and Subsistence, Causality and Dependence, Community.
Modality - Possibility or Impossibility, Existence or Non-Existence, Necessity or Contingence.

I don't understand this logic behind this concept very well - Are these different ways in which we judge and categorize? For example, can people have higher levels of Modality and less Quantity in their understanding?

If we say that the study of mathematics is a logical study, does that mean that people who study maths are observing Quality more? Subsequently does financial account focuses more on a type of Quantity understanding?