>a=1+4i; b=5-3i;
>a+b
 6+1i
>a-b
 -4+7i
>a*b
 17+17i
>a/b
 -0.205882352941+0.676470588235i
>fraction a/b
 -7/34+23/34i
>conj(a)
 1-4i