一块三角形的交通标志牌(如右图),它的面积大约是28平方分米,底是8分米,高大约是多少分米?
计算,能简算的要简算.0.32×2.5×12.5 3.6×0.81+0.36×1.9 4.05÷[1.8×(3.36﹣2.86)].
计算下面各题,能简算的要简算.5.95÷(1.2+0.5)×5 75÷(0.75×4)0.8×0.68×125 73.5×0.1+7.35×9.
计算下面各题,能简算的要简算.8.5×〔(2.36+2.42)÷0.25〕 3.9÷(1.3+0.6)×6 205×994.25×6.3+3.7×4.25 25.6﹣7.49﹣2.51 〔2.5﹣(6.8﹣4.9)〕×0.8.
递等式计算:(能简便计算的用简便方法计算)(1)3.6×1.25+0.32÷0.4(2)0.45×78.2+20.8×0.45+0.45(3)14.5+27.3+12.7+45.5(4)(0.25+0.125)÷(0.75×0.4)(5)6500÷0.125÷0.8(6)[(3.8﹣2.5)×0.4﹣0.1]÷0.04.
8.6×10.1 5.6×(12.5﹣8.5÷0.85)[(8.1﹣5.6)×0.9﹣1]×0.4 8.25×4.08+0.75×4.08+4.081.84÷[(28.02+11.98)×(62.8﹣62.3)].