直接写得数: 0.5×1.2= 0.963÷9= 1.85×5= 1.7÷0.27= 0.8×1.25= 7.7×0.5×0.2= (0.2+0.2+0.2)÷0.3= 4.2÷0.01= 21.8﹣7.2﹣2.8= 0.5÷0.5+(0.9﹣0.9)=
估算并计算: 495×3 503×6 712×4.
估算 (1)59.9÷3.1≈(2)2.92×8.1≈(3)11.9÷6.1≈ (4)03÷0.39≈(5)4.83÷0.21≈(6)4.8×0.49≈
估算; 78×32≈ 51×29≈ 440÷9≈ 378÷5≈
估算. 59×7≈ 71×9≈ 586×5≈ 613×3≈ 316×6≈
估算 13.258+6.969≈ 88.7﹣21.39≈