I have a view of complex numbers and the way they are taught. I think the whole concept of i as the sqrt(-1) is a terrible place to start. And calling it "imaginary" is worse yet. They should be called blue numbers, or vertical numbers, or something. They are anything but imaginary. It is about simple 2 dimensional numbering systems. The sqrt(-1) is actually an advanced topic, not a starting point. Let me explain. I view complex numbers as the general case and real numbers as a special (but simple) case. Things in nature generally have a magnitude and a direction, like impedance and phase, or momentum and direction. If you draw a magnitude and phase "arrow" on a two dimensional graph, you can expresses it as a vertical and horiziontal component. That's the "complex" plane. What is so complex about that. It's pretty simple. Why not call them simple numbers? And what is imaginary about the vertical component? In some representations the horizontal component is just as "imaginary", or hard to visualize. If you don't case about the phase or directionality you can just deal with 1 quantity, typically a real number. In reality there may be underlying 2-dimensional components but you can treat the whole as a real number. The whole idea of 2 dimensional numbers can be extended to 3 and more dimensions. what do you call the 3rd dimension? The really imaginary number? I'm not saying I have a cirriculum to teach complex math in Jr High, but sqrt(-1) is imaginary is not the place to start.