COMPLEX NUMBERS: X axis and the y axis, sum, product and conjugate of complex numbers.  Google Play  

Using
the options of this application you understand:  How to use the x axis and the y axis to graphically represent complex numbers.  How to sum two complex numbers as vectors.  How to sum algebraically complex numbers.  How to find the product of complex numbers.  How to use the conjugate of the denominator to simplify fractions with complex numbers in the denominator. 
Download 