With the complex numbers, we finally have an algebraically complete set. In symbols, the equation has a representation of the form with the numbers the zeros or roots of the polynomial. The reader might wonder why we should worry about all these different number systems. Knowing something about real numbers sheds a little light about rational numbers, and so on. The language of science is fundamentally mathematical, and requires familiarity with all the number systems we have discussed here.
Most technical subjects are technical because of an underlying dependence on mathematics.
The real world assumes a basic understanding of math to do science, engineering, computers, medicine, biology and business. Even gambling requires math if one wishes to win, since figuring probabilities is precisely how lotteries and casinos stay in business. The only skill more fundamental than math is the ability to read. Because nearly every career you can do absolutely depends on your math skills . How good you should get at a particular number system depends on what you do.