Editor: Math teacher Jeffrey Smith gets the math wrong in his commentary on “The American Dream.” (“Keep the American Dream Alive” Jan. 9). To start with, he extols the significance of a student leaping from a lower quintile of the population to a higher quintile, forgetting that movement within such a relational dataset has little significance for the nation as a whole. For every person who advances, someone else must necessarily drop into a lower quintile to take his or her place. In and of itself, the relational dataset shows no net gain or loss. A better math would be to compare the absolute numbers over time. For example, since 2008 all quintiles except the topmost have fallen in wealth. During other periods, all quintiles have risen. In all economic eras, the important questions have always been: 1) “Where is my next meal coming from?” and 2) “Am I sweating rent?” Few of Smith’s students, or any other students, or for that matter adults, are worried about quintiles. Quoting the “2.5 million STEMs needed by industry” is another common math mistake. In accepted math theory, that figure is not defined as a real number, since nothing has actually been counted to bring it into being. It is a literary construct, a propaganda term used by Silicon Valley mavens to lobby Congress for higher immigration quotas so they can lower wages. The 2.5 million is impressive and sounds like a number, but it’s not. It’s an emotion-loaded symbol posing as a number. The notion that American technologists will save the U.S. economy has been pushed hard in the media for the last 30 years. What always happens is this: When a technology is found to be commercially viable, U.S. banks and investment firms finance factories in China, India, Bangladesh, Mexico, Thailand or some other country that pays wages 10 cents on the dollar. Nowadays great things are only accomplished with cheap labor and other people’s money. The dollars are printed by the U.S. Federal Reserve at taxpayer expense, handed out to their banker buddies, and shipped overseas. America’s greatest export is its dollars. Smith is right that Americans, young and old, must study and master mathematics. Math will help them defend themselves from their numerous enemies: real estate hype agents, loan officers, car dealers (new and used), stock jobbers, investment “consultants,” military recruiters, advertisers, health insurance sales women, corporate and government bureaucrats and politicians, all of whom have been known to use dodgy math in their career paths. And yes, let’s not forget opinion writers in the local newspaper. Hopefully Smith’s “STEM” saviors won’t invent any more cell phone apps; that would just make his task in class more difficult.