1) (2,04:1/25 - 36,1:19/20)*5/13 - 0,6:0,9 = (51 - 38) * 5/13 = 13*5/13= 5
2) (3,6 - 1 целых 2/3) : (4 целых 1/15 - 2 целых 7/9)*2,6 = (3 6/10 - 1 2/3) / (4 1/15 - 2 7/9) * 2.6 = ( 3 18/30 - 1 20/30) / ( 4 9/135 - 2 105/135) * 2.6 = ( 2 48/30 - 1 20/30) / ( 3 144/135 - 2 105/135) *2.6 = 1 28/30 / 1 39/135 *2.6 = 58 * 135 * 2.6/ 30 * 174= 3.9