I'll have to explain a group of people how addition and subtraction works with complex numbers. At first I thought that it'll be quite easy to talk about 10 minutes. The problem is, that it's to easy and I am not able to fill the time.
My plan to this point is, that I'll show them the complex plane and show them an example for an addition and subtraction. Then I'll tell them how it is possible to calculate it without the plane.

Is there anything I could add except from that all numbers are in fact complex but have an imaginary part of 0?