Math Lingo vs. Plain English: Double Entendre

Abstract

Once upon a time, when was a teaching assistant, teaching a class of the kind mockingly called Math for Poets, obnoxious freshman said to me, Zero isn't a number. have forgotten my answer, but remember finding her remark a shocking expression of profound ignorance. Years later, it dawned on she was right! say I own a of calculus or I have a of friends at the Courant Institute, don't mean zero books or zero friends. don't even mean one book or one friend. mean two or more. what number means in plain English. read recently that the famous phenomenologist Edmund Husserl meant by number something greater or equal to 2. So did Plato. In mathematical talk, numberhas several meanings. None is the plain English meaning. The ordinary teacher, like back then, is so deeply embedded in lingo that he/she doesn't notice the inconsistency. But the inconsistency can confuse students. say math lingo,not language. It's a jargon, a semidialect of English (or some other natural language), not a complete language. can't say have a headache or You bore me in lingo. In lingo, a straight is the simplest example of a curve. In plain English, quite otherwise: a straight isn't a curve, and a curve isn't a straight In English, what we call a segment is just a line. What we call a line is an infinite line. Difference, product, factor, prime all have different meanings in plain English and in lingo. may ask a student, If you subtract zero from what's the difference? While answering math-linguistically, zero, she may be thinking, plain-Englishly, That's right! Who cares? What's the difference? In English, increases what you've got. In lingo, it may increase it, decrease it or neither, depending on whether you happen to be adding something positive, negative or zero. Correspondingly, decreases. In lingo, it may decrease or increase or neither. In English, and subtracting are opposite. In lingo, they're opposite, and yet they're the same! For adding a is the same as some other (its negative). In English, means repeated adding. It makes things bigger. In lingo, multiplying makes them bigger, smaller, or neither, depending on what you multiply with. Correspondingly, divide means cut into pieces, possibly equal pieces. In lingo, divide is the same as multiply, in the sense that dividing by a other than zero is the same as multiplying by some other (its reciprocal).