I was thinking that free education would extend up through 7th/8th grade, more for political reasons than for economic reasons. An educated citizenry is a prerequisite for democracy. Without it the whole system risks collapse.
But primary school should teach things necessary to evaluate the claims of others, not to prepare you for the working world, however. Reading, writing, and rithmetic are obvious ones. But instead of branching off into algebra/biology/geology/etc, I think they should teach probability & statistics, economics and finance, the scientific method in general (with the emphasis on the process, not on the findings), and a lot of history.
But primary school should teach things necessary to evaluate the claims of others, not to prepare you for the working world, however. Reading, writing, and rithmetic are obvious ones. But instead of branching off into algebra/biology/geology/etc, I think they should teach probability & statistics, economics and finance, the scientific method in general (with the emphasis on the process, not on the findings), and a lot of history.