a, 17.(-3)-17.7=17.(-3-7)=17.(-10)=-170
b, (-53).15+(-85).53=53.(-15)+(-85).53
= 53.(-15-85)=53.(-100)=-5300
c, 117.26-17.26= 26.(117-17)=26.100=2600
d, 13.8+87.8=8.(13+87)=8.100=800
2) 19
2) 19.(-15)+81.(-15)=(-15)(19+81)=(-15).100=-1500
17 . ( - 3 ) - 17 . 7
= 17 . ( -3 - 7 )
= 17 . ( -10 )
= -170