2×2/1×(2/15-3×5/6)+4/1
1) 3*5/6= 15/6= 5/2
2)2/15- 5/2= (2*2-5*15)/30= (4-75)/30=71/30
3)2*2/1=4
4)4*71/30=2*71/15=142/15=9*7/15
9*7/15+4/1=13*7/15