(a)  11 + (-7)

= 11 – 7

= 4

Therefore, sum is 4

(b) (-13) + 18

= -13 + 18

= 5

Therefore, sum is 5

(c)  (-10) + 19

= -10 + 19

= 9

Therefore, sum is 9

(d)  (-250) + 150

= -250 + 150

= - 100

Therefore, sum is – 100

(e) (-380) + (-270)

= - 380 – 270

= - 650

Therefore, sum is – 650

(f)  (-217) + (-100)

= - 217 – 100

= - 317

Therefore, sum is -317