Đáp án: a) 34.(66-5)-66.(34+5)
= 34.66-34.5-66.34-66.5
= (34.66 - 66.34) -34.5-66.5
= 0 + 5.(-34-66)
= 5.(-100)
= -500
b) -37+54+(-70)+(-163)+236
= (-37-163)+(54+236)-70
= -200 + 300 -70
= 100-70
= 30
c) -359+181+(-123)+350+(-172)
= (-359+350)+(181-172)-123
= -9 + 9 -123
= -123
d) -69+53+46+(-94)+(-14)+78
= (-69-94-14)+(53+46+78)
= -177 + 177
= 0
e) 2.(-4).6.25.(-7).5
= (2.5).(-4.25).(-7.6)
= 10.100.(-42)
= -42000
g) 42.48 - 24.34
= 42.24.2 - 24.34
= 24.(42.2-34)
= 24.(84-34)
= 24.50
= 1200
h) 4.(-8)-7.(-4)
= 4.(-8+7)
= 4.(-1)
= -4