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在学习有理数运算时,由于同学们对相关知识理解不透,往往会出现各种各样的错误,现将学习有理数运算时应注意的一些问题归纳如下,以期引起同学们重视:一、违反去括号法则例1计算:-56-(-56+35-23)+23错解:原式=-56+56+35-23+23=35剖析:本题错解的原因就是违反了去括号法则,去括号时,如果括号前面是“-”号,把括号和它前面的“-”去掉后,括号里的每一项都要改变符号,而在本题中,去括号时,只改变了括号里-56的符号,忘改变了+35和-23的符号。
When learning rational number operation, students often misunderstand relevant knowledge, and various mistakes often occur. Nowadays, some problems that should be noticed when studying rational number operation are summarized as follows, arousing great concern to students: Parentheses Law Example 1 Calculated: -56 - (- 56 + 35-23) +23 The wrong solution: the original = -56 +56 +35-23 +23 = 35 Analysis: The reason for the wrong answer is to break the rules to the brackets , To the brackets, if the parentheses in front of the “-” sign, the parentheses and it in front of the “-” removed, the brackets of each have to change the symbol, and in this question, to the parentheses, Only changed the brackets in the -56 symbols, forgot to change the symbols +35 and -23.