Binary number arithmetic

Perform the following decimal arithmetic operations in $8-$bit binary

Addition:

a$)77+15$

b$)92+9$

c$)50+15$

Subtraction:

a$)100-91$

b$)127-77$

c$)-7-9$

Multiplication:

a$)15*8$

b$)8*16$

Division:

a$)\frac{77}{15}$

b$)127-77$