(3 1/4 + 1 1/6 : 1 5/9) : 2 2/7 + 5 1/9 : 7 2/3 = 2 5/12
1) 1 1/6 : 1 5/9 = 7/6 : 14/9 = 7/6 * 9/14 = 1/2 * 3/2 = 3/4
2) 3 1/4 + 3/4 = 4
3) 4 : 2 2/7 = 4/1 : 16/7 = 4/1 * 7/16 = 7/4
4) 5 1/9 : 7 2/3 = 46/9 : 23/3 = 46/9 * 3/23 = 2/3
5) 7/4 + 2/3 = (21+8)/12 = 29/12 = 2 5/12