addition (of complex numbers) If the complex numbers z1 and z2 are represented by the points P1 and P2 in the complex plane in which z1=a+bi and z2=c+di, then z1+z2=(a+c)+(b+d)i. z1+z2 can be represented in the complex plane by such a point Q that OP1QP2 forms a parallelogram.

Related Terms: complex number, complex plane