异分母的分式加减法是分式运算的重点，必须认真学好．其学法是先通法，后巧法．一、掌握运算步骤，学好通法异分母的分式加减法的一般步骤是：（1）把各式的分母分解困式；（2）确定各分母的最简公分母；（3）利用分式的基本性质化异分母为同分母；（4）进行计算，最后结果化? Fractional addition and subtraction of the different denominator is the focus of fractional operations and must be carefully studied. The method of learning is the first method, then the method. First, the general steps of mastering the operation steps and learning the common addition and subtraction of the different denominator of the common method are: (1) Break down the denominators of various types; (2) Determine the simplest common denominator of each denominator; (3) Use The basic denominator of the fractional basic nature is the same denominator; (4) Calculate, and finally result?