IMO make learning programing (fun) a path to learning math (not fun). Once you understand mathematic fundamentals, understanding finance - and other such disciplines - comes naturally. You soon realize that most of (consumer) finance out there are marketing flush revolving around a few formulas.
Why is learning math not fun? For me, learning math (fun) was a path to learning programming (not fun). Even as someone who 'enjoys' programming as a hobby, I hate the actual coding part. The math is the fun part. And that rush of power you feel where the computer obeys your every wim is a nice bonus (more of a reason to learn bash et el.).
you're right, the fun factor is very subjective. However, wouldn't you agree that those who enjoy maths from the get-go will generally be successful in most modern education systems? The same is not true for those who have difficulties in maths but were never given a early-enough introduction to coding.