You hit the nail on the head there. And it's not just K-12 math, either. I don't know about Australia, but I can see what it's like here in the US.

I moved here 7 years ago, and my son has gone through a public elementary school and is currently in the last year of a public middle school. If it was just one year or just one teacher or even just one school (or one district), I could write it off to bad luck. Unfortunately, it's pretty clear that the whole system is abysmal.

As someone currently tutoring an 8th grader in math: The curriculum is not really much different than what I went through in the 80's and 90's. They're still learning Algebra going into High School, and lots of work with fractions, percentages, interest rates, area, volume and so forth leading up to it. The kids still loathe word problems.

The basics are just being taught differently.

Ah, but that was intentional! We didn't want people to really understand statistics, because that was governments' favourite tool to control the masses. ;-)

Agreed on k-12 maths, but the analysis of persuasive techniques was actually taught quite well and comprehensively, at least when I went through school (finished in 2011).