3/4 * 1/5 = (3*1) / (4*5) = 3/20
7/20 * 1 1/3 = 7/20 * 4/3 = (7*1)/(5*3) =7/15
8 * 5/6 = (8*5) / (1*6) = (4*5)/(1*3) =20/3= 6 2/3
2/3 : 4/5 = 2/3 * 5/4 = (2*5)/(3*4)= (1*5)/(3*2)=5/6
3/8 :9 = 3/8 * 1/9 = (3*1)/(8*9) = (1*1)/ (8*3)= 1/24
(3 1/3 )³= (10/3 ) ³ = 1000/27 = 37 1/27