1/3*3 3/5+2 1/4 :1 1/5*4/5 =

1/3*18/5+9/4:6/5*4/5
18/15+9/4*5/6*4/5
18/15+45/24*4/5
18/15+180/120
144/120+180/120
324/120
2 84/120
2 7/10

= ⅓ × 3 3/5 + 2 ¼ : 1 1/5 × 4/5
= ⅓ × 18/5 + 9/4 : 6/5 × 4/5
=18/15 + 9/4 × 5/6 × 4/5
= 6/5 + 9/6
= 36/30 + 45/30
= 81/30
= 27/10
= 2 7/10

Semoga berguna +_+