199.199*198-198.198*199的简便运算 18.9*178.178 +0.49-17.8*189.189_数学解答

199.199*198-198.198*199的简便运算 18.9*178.178 +0.49-17.8*189.189

人气：316 ℃　时间：2020-03-22 00:52:20

解答

199.199*198-198.198*199=(199+0.199)*198-(198+0.198)*199=199*198+0.199*0.198-198*199-0.198*0.198=018.9*178.178 +0.49-17.8*189.189 =18.9*(178+0.178) +0.49-17.8*(189+0.189)=18.9*178+18.9*0.178+0.49-17.8*...