1) 2,5 - 2 1/3 = 2 1/2 - 2 1/3 = 2 3/6 - 2 2/6 = 1/6

2) 1/6 * (-5 1/3) = 1/6 * (-16/3) = -8/9

3) 1 1/3 : (-5,6) = 1 1/3 : (-5 3/5) = 4/3 * (-5/28 ) = -5/21

4) -8/9 + (-5/21) = -(8/9 + 5/21) = -(56/63 + 15/63) = -71/63 = -1 8/63

ответ: -1 8/63