1.（2/18-3/18-1/18）X36
=2/18*36-3/18*36-1/18*36
=4-6-2
=-4
2.（1/4-1/2-1/8）X128
=1/4*128-1/2*128-1/8*128
=32-64-16
=-48
3.[9X(-4)]X(-1/4)
=9*(-4)*(-1/4)
=9*1
=9
4.2.25x(-2.3)X3/25
=2.25*3/25*(-2.3)
=-621/1000
5.(-2.1)X6.5X(-3/7)
=(-2.1)*(-3/7)*6.5
=0.9*6.5
=5.85