1.9+19.9+199.9+0.3解算

1.9+19.9+199.9+0.3解算 1.9+19.9+199.9+0.3怎样简算 1.9+19.9+199.9+0.3 如何简便运算 1.9+19.9+199.9+1999.9简算 1.9+19.9+199.9+1999.9+19999.9 1.9+19.9+199.9+1999.9+0.4 1999+199.9+19.9+1.9= 0.9 1.9 19.9 199.9用简算怎么算? 简便计算1.9+19.9+199.9-0.4 1.9+19.9+199.9+1999.9+19999.9=? 1.9+39.9+19.9+199.9+0.4巧算求答! 19999.9+1999.9+199.9+19.9+1.9怎么巧算'急啊