(3 целых 1/12+ 1 целая 5/12):1 целую 1/2

1) 3 1/12 + 1 5/12 = 4 6/13;
2) 4 6/13 : 1 1/2 = 4 12/26 : 1 13/26 = 4 12/26 * 1 13/26 = 4 12/26.

(3 1/12 + 1 5/12) : 1 1/2 = 4 6/12 : 1 1/2 = 4 1/2 : 1 1/2 = 9/2 : 3/2 = 3