If there is one thing the public school system should be able to achieve, it is to produce adults capable of simple arithmetic. So why are so many of us, including so many with professional degrees and 6 digit salaries, awash with debt? We know how to add up - the costs of our consumption - and we know how to subtract that total from our income and see whether the result is positive or negative. But we just don't do it. Rather we spend according to how rich we feel.