Are you a math teacher? If you are then you probably have built up a tolerance to the funny looks; a tolerance to the subtle comments that are meant to infer that you are VERY different from everyone else. You must have this tolerance or how else could you continue in your profession. I understand. I have it too.
But here is the thing. It dulls us to the messages around us. Something is wrong in in the state of math education. Most of us know this, though some still fight it. Most of us know that it is the charge of math teachers to make it better. We must raise an entire generation of children that meet math teachers and say, "Yeah, math was always too easy for me so I decided to do something difficult like teach grammar instead." That is our charge, and to make it happen we need to assiduously evaluate everything that we do. We must find the mistakes and fix them. I don't know if what I am about to propose a solution to is the most pressing problem, but it definitely is one. We may be able to learn something from the problem, and I hope something from my proposed solution. Here goes...
Let's take what a child is supposed to know about complex numbers after Algebra 2. Algebra 2 is or was a terminating course in high school math. So this may be all that any one every learns about these crazy things. Here are the objectives from the Algebra 2 book I am teaching out of during summer school:
- Simplify radicals containing negative radicands
- multiply pure imaginary numbers
- solve quadratic equations that have pure imaginary solutions
- add, subtract, and multiply complex numbers
- simplify rational expressions containing complex numbers in the denominator
This is really the first time that students have been exposed to these kinds of numbers. Some have heard about them and wondered what they meant. And what do get to find out about them. That the purpose of complex numbers is to be added, multiplied, subtracted and simplified. Imagine that you were trying to sell and innumerate person on the integers.
Stone Age Math Teacher: Hey, have you heard about this great new number -1?
Stone Age English Major: Cool what can you do with it?
Stone Age Math Teacher: You can add, subtract, multiply and divide with it. Pretty cool huh? And you can solve any subtraction problem if you allow a whole class of new numbers called the integers!
Stone Age English Major: Wow. Major. Let's go invent beer, so I can invent poetry.
A purpose for complex numbers must be the ground work to any introduction to these numbers. Many of you may feel that these numbers have no purpose. Or that maybe the purpose is to allow us to say that yes, every quadratic does have two solutions (if you count multiplicities). But no, the purpose is real. It is part of our everyday existence. Just as the reason that 1, 2, 3 came about was to help sheep herders keep track of the flock. We are talking real.
What is it. Yawn.... I will write that tomorrow.