Ask HN: How much logic/probability/statistics do you apply in your daily life?

Let me give you an example. Someone asked me to freelance a side project that will pay me X money. Then I could also study for an exam that if I pass it will net me a job that will be 40% of the money more than I get now. I estimate based on previous exams that my chance is about 10% of passing it lets say (because they select only the top 0.5%) (exact numbers don't matter). Now if I study, my chances would be highered by self-estimate to 15%. Then calculating how many hours of study for this 5% and then the amount of money it would net me for X years if I get this job and comparing it to the hourly that the side project will offer me is something I do often. Does this process sound familiar? It is difficult to explain to people that are not so much math aware that it doesn't matter if I don't pass the exams and my action of studying is actually netting me money because it increases the probability.