23 : (6 5/17 + 1 12/17) - (4 2/5 - 2 3/5) : 5 = 2 103/200
1) 6 5/17 + 1 12/17 = 7 + 17/17 = 8
2) 23 : 8 = 2 7/8
3) 4 2/5 - 2 3/5 = 3 7/5 - 2 3/5 = 1 4/5
4) 1 4/5 : 5 = 9/5 : 5/1 = 9/5 * 1/5 = 9/25
5) 2 7/8 - 9/25 = 23/8 - 9/25 =575/200 - 72/200 = 503/200 = 2 103/200 - несократимая дробь, так как 103 - простое число.