a) (218 +529 ) + ( 151 – 218 – 529 )
= 218 +529 + 151 – 218 – 529
= (217-218)+(529-529)+151
= 0 + 0 + 151
= 151
b) ( 113 – 135 + 49 ) – (113 +49)
= 113 – 135 + 49 –113 -49
= (113-113)+(49-49)-135
= 0 + 0 - 135
=-135
c, ( 613 – 135 + 49 ) – (- 35 +49) - 613
= 613 – 135 + 49 +35 -49 - 613
= (613-613)+(49-49)+(-135+35)
= 0 + 0 - 100
= -100