计算:
(1)(-11)×+(+5)×+(-137)÷5+(+113)÷5;
(2)-8-[-7+(1-×0.6)÷(-3)].
网友回答
解:(1)(-11)×+(+5)×+(-137)÷5+(+113)÷5
=(-11)×+(+5)×+(-137)×+(+113)×
=×[(-11)+(+5)+(-137)+(+113)]
=×[-6+(-24)]
=×(-30)
=-6.
(2)-8-[-7+(1-×0.6)÷(-3)]
=-8-[-7+(1-×)×(-)]
=-8-[-7+(1-)×(-)]
=-8-[-7+×(-)]
=-8-(-7-)
=-8+7
=-.
解析分析:(1)逆用乘法分配律计算;
(2)按照有理数混合运算的顺序,先乘除最后算加减,有括号的先算括号里面的.
点评:要正确掌握运算顺序,即乘方运算(和以后学习的开方运算)叫做三级运算;乘法和除法叫做二级运算;加法和减法叫做一级运算.在混合运算中要特别注意运算顺序:先三级,后二级,再一级;有括号的先算括号里面的;同级运算按从左到右的顺序.