Gary Rubenstein has been writing a series of posts on the question of whether the math curriculum is useful. Some parts of it are indeed useful, others not so much. In this post, he describes the “useless” topics.

He writes:

I’d estimate that about 15% to 20% of school time in K-12 is spent on math. Elementary and middle schools often have their students do 90 minutes of math a day. And it is common for students to take a math class every year throughout high school.

In my last post I listed a meager six math topics that I consider ‘useful’ and by that I mean that those math skills are really needed by adult consumers and also, to some degree, in a lot of professions. And if you believe me about this and you think that any math that is not useful should not be taught in school you might wonder how much time should be dedicated to those topics throughout a students schooling. Now I’m not saying that I think that we should cut all topics besides these few but if I had to answer how long it could take to teach those, I’d say that we could do it in about 1/3 the amount of time. Math would be a thing like music, art, or physical education.

It’s still an interesting thing to think about, though, because it gets to the fundamental question of ‘what is the purpose of learning math?’ or ‘what is the purpose of learning anything for that matter?’ or ‘what makes this thing better to learn than that thing?.’ I will eventually provide my opinions on these questions.

But before we cut 2/3 of the time that we dedicate to math, we should take a look at what sorts of things would we be depriving the students of and whether there would be negative side effects of these discarded topics.

In Part 2, I mentioned a topic that I said was not ‘useful’ of finding the prime factorization of composite numbers. While it is true that hardly anyone in their adult lives are ever asked to break 555 into 5*3*37, maybe the ‘use’ of this skill is not so direct. The ‘use’ of some ‘useless’ topics is that they are prerequisite skills to more complicated topics in future years and those more complicated topics might be ‘useful’ in some science applications. So some ‘useless’ topics might have some utility as scaffolding to other topics.

Another reason that something like factoring has more ‘use’ than it at first seemed is that prime numbers are really important in more advanced math. They are the building blocks of all other numbers. Maybe someone who loves factoring eventually becomes a math major and they use advanced factoring to create a new cryptography method based on it.

Open the link and keep reading.