在初中数学教学中,谈到“换元”会马上想到用换元法解某些特殊方程。其实“换元”作为一种数学的思想方法,不仅出现在解某些特殊方程中,还渗透、隐含在初中数学的其它的内容之中。我们试从教材与教学的角度谈谈“换元”思想的渗透及“换元法”的应用。一、“换元”作为一种数学思想、早已渗透在解方程之前的代数内容之中。我们可以找到其渗透的痕迹。 1.用字母表示数、求代数式的值,尽管是用“字母(元)”替换“数”或用“数”替换“字母(元)”,其实都可看作是“换元”意识的表现。 2.代入消元法解方程组中的“代入”渗 In the mathematics teaching of junior high school, talking about “changing yuan” will immediately think of using the yuan-changing method to solve certain special equations. Actually, “changing yuan” as a mathematical method of thinking not only appears in the solution of certain special equations, but also penetrates and is implicit in the other contents of junior high school mathematics. We try to talk about the infiltration of the idea of ​​“changing yuan” and the application of the “changing yuan method” from the perspective of teaching materials and teaching. First, “changing yuan” as a mathematical idea, has already penetrated into the algebraic content before the solution equation. We can find traces of its penetration. 1. Alphanumeric representations and algebraic expressions, albeit substituting “letters (elements)” for “numbers” or “numbers” for “letters (elements),” can actually be considered as “escape” consciousness. which performed. 2. Substitute into the elimination method to solve the equation