把一个横放着的长40厘米、宽15厘米、高10厘米的长方体木块沿水平方向平均分成三块后,木块的表面积增加了多少平方厘米?
计算下面各题,能简算的要简算.0.125×3.21×8 7.3×1.2﹣1.8 20÷0.4÷2.5 8.6×2.6+1.4×2.6 4.6×102.
计算能简便的要简便:(1)2.5×6.73×4 (2)18.6×5.8÷0.6 (3)3.25×0.8+6.75÷1.5(4)(6.3×1.4+3.7×1.4)×2.5 (5)2.4﹣25.3÷5.5+7.6 (6)3.8÷1.25÷1.25÷8÷8.
神机妙算细又巧.(计算下面各题能简算的要简算)21.28﹣21.28÷7×3 0.32×25×12.5 2.5×4.7﹣2.5+2.5×6.3 (77.4﹣3.096÷0.4)÷0.03 7.74×(2.8﹣1.3)+1.5×2.26.
用简便方法计算.①4.45+0.63+5.55 ②45.5﹣(0.98+5.5) ③0.96﹣0.28+0.04﹣0.72.
直接写得数:1.25×8= 5×2.4= 0.36÷3.6= 5.6+4.04= 4.6×0.1=72.5÷0.01= 0.8×0.05= 6.04﹣0.4=1÷4= 48.9﹣(8.9+4.96)= 27.5×11÷27.5×4=