Ultimately I didn't know anything when I left home at 18 and I figured it out. Other people can too. How long does it take to learn how to drive, open a checking account, cook, pay bill, etc. after all ? You can learn these things privately over the Internet so there's no longer a social stigma holding you back. To digress, I eventually taught my older brother responsibility, job skills (he worked at my business), how to file taxes, basic math, etc. He became even more bitter and resentful and then one day broke down and admitted how painful it is to know nothing useful and most of what he does know he had to learn from his little brother. But eventually he started just Googling instead of calling me when he had a question he should know the answer to.
I truly feel sorry for these lost souls and if I hadn't been naturally good at math, I'd likely be one of them.