五上数学小数除法‖简便计算四大类型 一、除法的性质(一个数连续除以两个数,等于除以这两个数的积) a÷b÷c=a÷(b×c) 8÷0.125÷0.8 =8÷(0.125×0.8) =8÷0.1 =80 75÷0.25÷4 =75÷(0.25×4) =75÷1 =75 二、商不变的性质(被除数和除数同时扩大相同的倍数,商不变。) 1.2÷2.5 =(1.2×4)÷(2.5×4) =4.8÷10 =0.48 50÷12.5 =(50×8)÷(12.5×8) =400÷100 =4 三、同级运算带符号搬家 12.5÷0.4×8 =(12.5×8)÷0.4 =100÷0.4 =250 72×25÷29 =72÷9×25 =8×25 =200 四、去括号(括号前是"÷",去括号要变号) 36×20÷(9÷5) =36×20÷9×5 =36÷9×20×5 =4×20×5 =80×5 =400 8.4÷(2.1×0.4) =8.4÷2.1÷0.4 =4÷0.4 =10
