10 questions: Basic complex-number mix

20 questions: Imaginary unit and powers of i

20 questions: Complex-number arithmetic

20 questions: Conjugate and modulus

20 questions: Division by complex numbers

20 questions: Quadratic equations with complex roots

20 questions: Relations between roots and coefficients

30 questions: Remainder theorem and factor theorem

50 questions: Polynomial equations

100 questions: Comprehensive review