A week ago Andrew Hacker asked on the New York Times editorial page “Is Algebra Necessary?” and concluded for most students it isn’t. 
The first practical thing that comes to mind is all the reports of average salaries of jobs requiring only a bachelor’s degree. Depending on which list you look at, the jobs with the top five or top ten salaries are all jobs that require at least algebra. Science, technology, engineering, and mathematics (STEM) jobs requiring only a bacherlor's degree pay around half again as much as non-STEM jobs requiring the same amount of education. There’s clearly a practical monetary benefit to learning math.
But what about people going into non-STEM fields? Hacker says they are discouraged from school by having to learn math they’ll never use. He suggests offering these students classes in practical quantitative skills but not formal algebra. My high school took a similar approach. We had to select three subjects to study at the Higher Level and three at the Subsidiary Level. Two of them had to be languages. But for non-mathematical students, there was an option of “math studies” that omitted calculus in favor of statistics and quantitative skills, similar to what Hacker calls for. My STEM classmates always asked why they couldn’t do that with languages and have options for "English studies’"and "Spanish studies"? At the beginning of the program, according to my classmates, I held up my hands like a crucifix in a horror movie in angst when the teacher asked me questions in Spanish at full conversational speed. By the end of the program we had to be fully proficient. A professor from another school, who we had never met before, interviewed us completely in Spanish and asked us to discuss topics like symbolism and foreshadowing in various stories and plays we read throughout the program. I sometimes think how different my world view would be if my high school had indulged my technical interests and not bothered me with stuff that I would never directly use in engineering like South American literature.
In addition to these collateral benefits of rounding out education, algebra and calculus have practical applications in all areas of life. The concept of one set of number being related to another set of numbers by a function that can be represented by a graph or by an equation crops up everywhere in life. The concepts of rate of change, rate of change of the rate of change, and area under a curve, i.e. basic calculus, are equally ubiquitous.
Even outside of jobs, math is necessary in public policy questions. In my community, a small group of people oppose the deployment of wireless water meters because of fears of the RF radiation. If the critics were more comfortable with math and meter manufacturers discussed the duty cycle and field strength over distance compared to other common sources of RF, I suspect they would drop their opposition. (I am currently trying to get an interview with the critics and am keeping an open mind.)
The more prosaic benefit of “jobs” should not be dismissed. We often hear that availability of jobs is people’s biggest concern. Today people compete for jobs in a global marketplace that includes countries where it’s widely understood that STEM is the ticket to affluence. Efforsts to make STEM classes more approachable to non-technical people are great, but all such efforts must focus on increasing students’ understanding of math.
