B1:
a) 12.(-5).(-2).(-6)=[12.(-6)].[(-5).(-2)]=-72.10=-720
b) 25.(-5).4.(-20)=(25.4).[(-5).(-20)]=100.100=10000
c) (-4).7.11.(-25)=(7.11).[(-4).(-25)]=77.100=7700
d) 125.(-7).(-8).(-2)=[125.(-8)].[(-7).(-2)]=-1000.14=-14000
B2:
a) (-34).11=-374
b) (-23).101=-2323
c) 205.(-21)=-4305
d) 31.(-99)=-3069
B3:
a) (43-13).(-3)+27.(-14-16)=30.(-3)+27.(-20)=-90-540=-630
b) (-72).(34-12)-34.(12-72)=(-72).22-34.(-60)=-1584+2040=-456
c) (34-14).(-5)+15.(-14-6)=20.(-5)+15.(-20)=-100-300=-400
d) (-42).(35-16)-35.(16-42)=(-42).19-35.(-26)=-798+910=112
