Add or subtract the following numbers in the specified base:

a$.4DF{B}_{\text{h}\text{e}\text{x}}+D62E{7}_{\text{h}\text{e}\text{x}}$

b$.ED{301}_{\text{h}\text{e}\text{x}}-C{O}_2{3}_{\text{h}\text{e}\text{x}}$

C$.{1001001}_{\text{b}\text{i}\text{n}}+{111}_{\text{b}\text{i}\text{n}}+{11010}_{\text{b}\text{i}\text{n}}$