=1-0.5*1/3*-7
=1-0.5/3-7
=-6-0.5/3
=-18/3-0.5/3
=-18.5/3
答案应该是负的三分之十八点五。
(1)-1的四次方-(1-0.5)*1/3*[2-(-3²)]
=1-1/2×1/3×(-7)
=1+7/6
=2又1/6
(2)-2²*(-1/2)+8/(-2)²
=-4×(-1/2)+2
=2+2
=4
(3)(7/9-5/6+11/18)*18-1.45*6+3.95*6
=7/9×18-5/6×18+11/18×18-(1.45-3.95)×6
=14-15+11-(-2.5)×6
=14-15+11+15
=25
(4)4又1/2*[-9*(-1/3)²-0.8]/(-5又1/4)
=4½×(-9×1/9-0.8)/(-5¼)
=9/2×(-9/5)×(-4/21)
=54/35