69 12/13 + 4 1/13 - 5*(70,84 - 67,4) - (86/93 + 3 1/3) : 3/31 = 12,8
1) 69 12/13 + 4 1/13 = 74
2) 70,84 - 67,4 = 3,44
3) 5 * 3,44 = 17,2
4) 74 - 17,2 = 56,8
5) 86/93 + 3 1/3 = 86/93 + 3 31/93 = 3 117/93 = 4 8/31
6) 4 8/31 : 3/31 = 132/31 * 31/3 = 44
7) 56,8 - 44 = 12,8