One of the common subjects of discussions these days is the appropriate education for children that will make them productive citizens in adulthood. One skill is math, but I have discussed that often in the past.
I have two pieces of relevant experience. First I spent 15 years in the non-profit educational world supporting every imaginable innovation in education as well as working to modify the local school board in San Francisco. I learned that no institutional change will significantly improve the outcome of education.
Secondly I raised 3 children. All three have been successful in the world. The are highly competent individuals. Each has a different set of skills and talents but they are highly effective and competent in the marketplace.
Therefore with modesty, I suggest that what children find most effective in their training that carries over to adulthood are the skills of self management.
Self management tends to be an automatic quality in an oldest child, in families with multiple children, the oldest child is often left with responsibility for the younger siblings. The consequences are an ability to plan, calculate and cope with the world. Therefore it become important to pass on this skill to all the children involved.
I found the most effective approach was to give children, from a very young age, total responsibility for some modest projects. For a very young child it might be 'please get the groceries out of the car and bring them in' for an older child it might be ' we need two quarts of milk, can you go get them for us, here is $10?'
These are examples of self directed self managed projects. The more the child is given this type of responsibility the more self management they will have... the greater will be there confidence as adults. Today a similar project might be to clean something or build something fairly complex that requires learning from a YouTube video.
Self management is a foundation for managing others. Both skills are permanently part of our society and will always be highly rewarded.