(2 целых 1/4 +3 целых 2/3) : (8.5-1целая 2/3) умн. на

(2 1/4 + 3 2/3) : (8,5 - 1 2/3) * 1,2 = 1 8/205.

1) 2 1/4 + 3 2/3 = 2 + 3 + 1/4 + 2/3 = 5 + (1 * 3)/(4 * 3) + (2 * 4)/(3 * 4) = 5 + 3/12 + 8/12 = 5 + (3 + 8)/12 = 5 + 11/12 = 5 11/12;

2) 8,5 - 1 2/3 = 8 5/10 - 1 2/3 = 8 1/2 - 1 2/3 = 8 - 1 + 1/2 - 2/3 = 7 + (1 * 3)/(2 * 3) - (2 * 2)/(3 * 2) = 7 + 3/6 - 4/6 = 7 - 1/6 = 6 + 6/6 - 1/6 = 6 5/6;

3) 5 11/12 : 6 5/6 = (5 * 12 + 11)/12 : (6 * 6 + 5)/6 = (60 + 11)/12 : (36 + 5)/6 = 71/12 : 41/6 = 71/12 * 6/41 = (71 * 6)/(6 * 2 * 41) = 71/82;

4) 71/82 * 1,2 = 71/82 * 12/10 = (71 * 2 * 2 * 3)/(2 * 41 * 2 * 5) = 213/205 = 1 8/205.