进行有理数的混合运算时,应按照先算乘除,再算加减,按有括号的先算括号里的顺序进行.有些同学由于对运算法则和运算律掌握不熟,再加上粗心大意,在运算中常出现这样或那样的错误.一、随心所欲,乱造“运算律” When carrying out a rational number of mixed calculations, it should be calculated by multiplying and dividing, and then adding and subtracting, according to the parentheses in the order of the first parentheses. Some students are not familiar with the algorithm and operation law, coupled with carelessness, in There are often one or more mistakes in the operation. One, arbitrary, invented “operation law”