“设而不求”是数学解题中一种比较有效的手段,在初中数学化简、求值中它有重要的应用价值,在直接求解很困难时,可根据情况设出一些未知量,根据已知量与未知量之间的关系,建立式子,此时用“设而不求”的思想方法,反而可以使问题轻松解决。如求三角形的面积,解题中我们会发现要单独分别求出底和高,往往比较难,但求出底与高的积会很容易,而知道底与高的积,三角形面积也求出来了,直接代入公式,便是一条可行的捷径。 “Set up without seeking” is a more effective method in mathematics problem solving. It has important application value in mathematics simplification and evaluation of junior middle school. When the direct solution is difficult, some unknowns can be set according to the situation. Quantity, based on the relationship between the known quantity and the unknown quantity, establishes the formula. At this time, the “thinking but not seeking” method of thinking can be used to solve the problem easily. Such as the area of ​​the triangle, in the problem we will find that to separately calculate the bottom and height, it is often difficult, but the product of the bottom and height will be easy, and know the product of the bottom and height, the area of ​​the triangle is also obtained It is a feasible short cut to directly substitute the formula.