先乘除,后加减啊。有括号先算括号里的
解:
(-2/3)×(-5/6)-(-3/4)÷(-4/9)+(-5/6+2/3)÷(-7/12)×7/2=
(-2/3)×(-5/6)-(-3/4)×(-9/4)+(-5/6+4/6)×(-12/7)×7/2=
(5/9)-(27/16)+(-1/6)×(-6)=
(80/144)-(243/144)+1=
(-163/144)+(144/144)= - 19/144
(-2/3)×(-5/6)-(-3/4)÷(-4/9)+(-5/6+2/3)÷(-7/12)×7/2
=2/3×5/6-3/4÷4/9-(5/6+2/3)÷7/12×7/2
=5/9-27/16-3/2×12/7×7/2
=-163/144-9
=-1459/144
应该是这样
(-2/3)×(-5/6)-(-3/4)÷(-4/9)+(-5/6+2/3)÷(-7/12)×7/2
=5/9-27/16+(-1/6)*(-12/7)*7/2
=5/9-27/16+1/3
=8/9-27/16
=128/144-243/144
=-115/144