括号六分之一减三分之二加七分之三乘括号负四十二

原式=-3.5-[7/3+1/2-(11/6-25/4)-1/2]
=-3.5-[7/3-11/6+25/4]
=-7/2-7/3+11/6-25/4
=-(14/4+25/4)-(14/6-11/6)
=-39/4-3/6
=-39/4-1/2
=-39/4-2/4
=-41/4