((2 1/3 - 1 7/9) : 30/49) + 11 5/6=
2 1/3 - 1 7/9=7/3-16/9=(7*3-16)/9=5/9
5/9:30/49=(5*49)/9*30=49/54
49/54+11 5/6=49/54+71/6=(49+71*9)/54=
=688/54=12 40/54=12 20/27