五上数学重点‖小数除法的简便计算 1.除法的性质。 9÷0.125÷8 =9÷(0.125×8) =9÷1 =9 7.2÷(0.9×0.4) =7.2÷0.9÷0.4 =8÷0.4 =20 2.商不变的性质。 5.6÷3.5 =(5.6÷0.7)÷(3.5÷0.7) =8÷5 =1.6 1.2÷0.25 =(1.2×4)÷(0.25×4) =4.8÷1 =4.8 3.拆数。 7.2÷1.8 =7.2÷(0.9×2) =7.2÷0.9÷2 =8÷2 =4 4.同级运算,带符号搬家。 0.16×5÷0.16×5 =0.16÷0.16×5×5 =1×5×5 =25 5.去括号。 5.4×(0.25÷0.9) =5.4×0.25÷0.9 =5.4÷0.9×0.25 =6×0.25 =1.5 6.除法“分配律”。 (13.5+8.1)÷0.9 =13.5÷0.9+8.1÷0.9 =15+9 =24
