What is algebra anyway? It’s a huge subject, but at its heart, it’s about relationships. How does a change in one quantity affect another quantity when they are related in a certain way? Hacker suggests that we need arithmetic but don’t need algebra. But it’s really difficult to separate these two skills. Algebra and geometry, another subject Hacker could do without, help develop logical skills and abstract reasoning so we can understand why we are making less money than before if we get a 20 percent pay cut followed by a 20 percent raise (or a 20 percent raise followed by a 20 percent pay cut—hello, commutative law of multiplication!) or how much merchandise we can purchase if we have $100 and a 25 percent off coupon.
One fallacy in Hacker’s reasoning is clear: Why single out mathematics? Yes, a knowledge of calculus may or may not help one negotiate through traffic or connect one’s computer to the Internet, but the same could be said for many other disciplines. How does knowing whom Hamlet killed accidentally help one be a better consumer? Does knowing the history of the Spanish-American War help one complete one’s tax return?