将含有两种或两种以上数量的应用题,用一种数量中的一份或若干份去代替其他数量中的数值相等的若干份或一份,从而求出未知数的方法,叫做等量代换法。用等量代换法解答某些应用题,算理易于接受,解题过程简捷,有利于开拓思路,为中学阶段系统学习方程打下基础。 A method that involves two or more applications, replacing one or more of the other numerical equivalents with one or more of the quantities to obtain an unknown quantity, is called an equivalent quantity Change method. Equivalent substitution method to solve some of the questions, easy to accept the calculation, the problem-solving process is simple, is conducive to developing ideas, and lay the foundation for the system learning equation in the middle school stage.