From my encounters with mathematically unskilled people: The usage of percentages is very confusing. As in in it is used in "1 in 100" but also there is this "6

From my encounters with mathematically unskilled people: The usage of percentages is very confusing. As in in it is used in "1 in 100" but also there is this "6% increase" which is used for factors 1.06, and that the reciprocal calculation is not a "6% decrease" but a "5.6% decrease". Then on top come usages of yearly or monthly interest rates, etc. In each context, the percentage needs to be handled and understood differently, which means that even though percentages are everywhere, the knowledge does not automatically "solidify" upon being exposed to percentages for these folks.