a)(-45).312-312-54.312
=312.[(-45)-1-54]
=312.(-100)
=-31200
b)217.(-46)-217.15-217.40+27
=217.[(-46)-15-40]+27
=217.(-101)+27
=217.[(-100)+(-1)]+27
=-21700+(-217)+27
=-21700+(-190)
=-21890
-43.15+43.48-48.43+48.15
=(-43.15+48.15)-(43.48-48.43)
=5.15-0=75