a) 11/18 + 17/24
= 44/72 + 51/72
= 95/72
b) -29/24 + 17/16
= -58/48 + 51/48
= -7/48
c) -5/12 + (-17/16)
= -20/48 - 51/48
= -71/48
d) -13/8 + (-17/12)
= -39/24 - 34/24
= -73/24
e) 13/25 - 17/40
= 104/200 - 85/200
= 19/200
f) -17/27 - 19/36
= -68/108 - 57/108
= -125/108
g) -13/40 - (-21/50)
= -65/200 + 84/200
= 19/200
h) -19/32 - (-17/48)
= -57/96 + 34/96
= -23/96
