0．7777×0．7＋0．1111×2．1的简便运算
问题描述：
0．7777×0．7＋0．1111×2．1的简便运算
急
答
0.7777X0.7X3+0.1111X2.1X3=nX3 0.7777 x 2.1 + 0.3333 x 2.1=n x 3 (0.7777+0.3333) x 2.1 = n x 3 (0.7777+0.3333) x 2.1 ÷ 3 = n x 3 ÷ 3 (0.7777+0.3333) x 0.7 = n 1.111x 0.7 = n n=0.7777