Tính hợp lí: 34 + 35 + 36 + 37 - 14 - 15 - 16 - 17

Tinh hop li :
a,34+35+36+37-14-15-16-17
b,271-[(-43)+271-(-17)]
c,31.(-18)+31.(-81)-31
d,(-78).11
e,(-12).47+(-12).52+(-12)
f,(-48)+48.(-78)+48.(-21)
g,35.18-5.7.28
h,45-5.(12+9)
i,5.(-8).2.(-3)
j,3.(-5)mu2+2.(-5)-20