(1/4÷3/8+2/5)X1/2=(8/12+2/5)x1/2=64/60ⅹ1/2=8/15,那么积就是8/15化成小数是约等于0.53。
(1/4÷3/8+2/5)×1/2
=(2/3+2/5)×1/2
=1/3+1/5
=8/15
(1/4÷3/8+2/5)X1/2=(1/4x8/3+2/5)x1/2=(2/3+2/5)x1/2=2/3x1/2+2/5x1/2=1/3+1/5=8/15