0.24x2.5x12.5=0.4x0.6x2.5x12.5=(0.4x2.5)x0.6x12.5=0.6x12.5=0.3x2x12.5=0.3x25=7.5
转化成分数约分口算即可:24/100*10/4*100/8=15/2
0.24=0.3*80.3*2.5=0.07512.5*8=100100*0.075=7.5
转化成分数最简单