2/2n-m/n-3m/3n=(2*3)/(2n*3)-(m*6)/(n*6)-(3m*2)/(3n*2)=6/6n-6m/6n-6m/6n=6/6n=1/n先化成同分母分数,然后再相减,得到结果后再化简就是1/n了,注:因无法打出分数的形式,"/"表示分数线,"/"前面的表示分子,"/"后面的表...