(7:5/6-81/9)*2 2/5:((3/8+5/6+5/12)*8/25)=

1) 7: 5/6 = 7 * 6/5 = 42/5 = 8,42) 8,4 - 81/9 = 8,4 - 9 = -0,63) -0,6 * 2 2/5 = -0,6 * 2,4 = -1,444) 3/8 + 5/6 = 9/24 + 20/24 = 29/245) 29/24 + 5/12 = 29/24 + 10/24 = 39/246) 39/24 * 8/25 = 13/257) -1,44 : 13/25 = -144/100 * 25/13 = -36/13 = -2 10/13