hey mate,
Addition for complex numbers is defined as follows,
given two complex numbers z1,z2 where
z1 = a1 + b1i , z2 = a2 + b2i
then
z1 + z2 = (a1 + a2) + (b1 + b2)i
Similarly for subtraction
z1 - z2 = (a1 - a2) - (b1 - b2)i
Hope this points you in the right direction,
Regards,
David
ps - message me if you require any further assistance