在解题中出现错误是难免的,也是正常的.但必须弄清产生错误的原因,掌握正确的解答方法,只有这样才能逐步形成数学基本技能和能力.本文就有理数中解题易犯的错误归纳剖析如下.一、符号错误从某种意义上说,有理数运算的难点在符号.例1计算:(-7)×(-5)-90÷(-15).错解原式=35-(+6)=29.辨析此题错在把90前面的“-”既当作运算符号,又当作性质符号.应该明确,对于符号“-”在运算中只能当作二者的一种. It is inevitable and normal to find mistakes in solving problems, but we must understand the causes of mistakes, master the correct solutions, and only then can we gradually form the basic skills and abilities of mathematics. Inductive analysis is as follows: First, the wrong symbols In a sense, the rational number of arithmetic difficulties in symbols. Example 1 Calculated: (-7) × (-5) -90 ÷ (-15). The original wrong format = 35- (+6) = 29. Discrimination This problem in front of the 90 “- ” as both operators, but also as a character symbol. It should be clear that the symbol “- ” can only be used in the operation as A kind of both.