**Title:** Classifying Complex Numbers

**Description:**
This lesson helps students distinguish between strictly complex numbers, strictly real numbers and strictly imaginary numbers while learning that real numbers and imaginary numbers are subsets of the set of complex numbers.

**Standard(s): **

[MA2013] AL1 (9-12) 18: Solve quadratic equations in one variable. [A-REI4]

[MA2013] AL2 (9-12) 1: Know there is a complex number *i* such that *i*^{2} = -1, and every complex number has the form *a* + *bi* with *a* and *b* real. [N-CN1]

[MA2013] ALT (9-12) 1: Know there is a complex number *i* such that *i*^{2} = -1, and every complex number has the form *a* + *bi* with *a* and *b* real. [N-CN1]

[MA2013] MI1 (9-12) 4: Explain the development and uses of sets of numbers, including complex, real, rational, irrational, integer, whole, and natural numbers. (Alabama)

[MA2013] PRE (9-12) 1: (+) Represent complex numbers on the complex plane in rectangular and polar form (including real and imaginary numbers), and explain why the rectangular and polar forms of a given complex number represent the same number. [N-CN4]