=3/4 *7/8*14/15*（4/9+2/15）*15/2*3/20*5*2/3=3（4/9+2/15）=26/15
3/4÷7/8÷15/14 =3/4×8/7×14/15 =4/5（4/9＋2/15）÷2/15 =4/9×15/2+2/15×15/2=10/3+1=13/3 3/20÷ 0.2×2/3 =3/20÷1/5×2/3 =3/20×5×2/3 =1/2
自己做才能会啊
