Some people can't do
any math in their heads, and are often just as helpless with
pencil and paper. They are not
good at math.
When I was little they told me that these people are usually killed by their own stupidity before reaching the age of 18. Or they go to pricey liberal-arts colleges and learn bad things and take up with bad people and become lesbians or anarchists or porn stars or lesbian anarchist porn stars and spit in the face of their hard-working middle-class church-going red-blooded American parents, who have, after all, given everything for them.
Then they would graduate with tens of thousands of dollars of debt - not too mention the interest, which, after 17+ years of education, they still cannot calculate.
I broke form. I go to a land-grant school, where the engineer to lesbian anarchist porn star ratio is about 15:1. Lesbian anarchist porn stars and others who are bad at math are usually not technologically savvy beyond maintaining their own ass web sites.
See also clueless Mac user.