(4 5/12 + 1 3/4) : (6 2/15 - 1 1/5) = 1 целая 1/4
1) 4 5/12 + 1 3/4 = 4 5/12 + 1 9/12 = 5 14/12 = 6 2/12 = 6 1/6
2) 6 2/15 - 1 1/5 = 6 2/15 - 1 3/15 = 5 17/15 - 1 3/15 = 4 14/15
3) 6 1/6 : 4 14/15 = 37/6 : 74/15 = 37/6 * 15/74 = (1*5)/(2*2) = 5/4 = 1 1/4