: -2 0.450.18300 0.9 85 100 0.90.9100= 0.81100= 81( ) 100 1100.9 85 100 0.8110+81= 8.1+81= 89.1( ) 0.90.9110=0.81110=89.1( ) . 110 可以用10块的面积,加上100块的面积。. . : . :. (1) 4.078.69.125(2) 18.45.11.7(3) 5.670.210.62. : . : 720.81+10.4= 58.32+10.4= 68.72 7.062.4-5.7= 16.944-5.7= 11.244 0.450.18300= 0.081300= 24.3 . 0.71.2 1.20.7(0.80.5)0.4 0.8(0.50.4)(2.4+3.6)0.5 2.40.5+3.60.5 = 0.65201= 0.65(200+1) = 0.65200+0.65 0.254.784= 0.2544.78 . = = + =1 4.784.78130 0.65130.65. 0.0340.50.6 1020.454.80.25 2.330.