13 2/5 - 11 1/5 : 9 1/3
1) 11 1/5 : 9 1/3 = 56/5 : 28/3 = 56/5 * 3/ 28 = 6/5 = 1 1/5
2) 13 2/5 - 1 1/5 = 12 1/5
3.6 + 4.8* (8.3/4 - 7 5/6)
1) 8 3/4 - 7 5/6 = 8 9/12 - 7 10/12 = 105/12 - 94/12 = 11/12
2) 4.8 * 11/12 = 4 4/5 * 11/12 = 24/5 * 11/12 = 22/5
3) 3.6 + 22/5 = 3 3/5 + 22/5 = 18/5 + 22/5 = 40/5 = 8