( - 1 2/5 + (- 3,6) + (2 5/6 + (- 2/3)) = - 2 5/6
1) 2 5/6 + (- 2/3) = 17/6 - 2/3 = 17/6 - 4/6 = 13/6 = 2 1/6;
2) - 1 2/5 + (- 3,6) = - 7/5 + (- 36/10) = - 14/10 + (- 36/10) = - 50/10 = - 5;
3) - 5 + 2 1/6 = - 4 6/6 + 2 1/6 = - 2 5/6
(- 5/8 + (- 3/4) + (- 7,6 + (- 2 2/5)) = - 11 3/8
1) - 7,6 + (- 2 2/5) = - 76/10 + (- 12/5) = - 76/10 + (- 24/10) = - 100/10 = - 10;
2) - 5/8 + (- 3/4) = - 5/8 + (- 6/8) = - 11/8 = - 1 3/8;
3) - 1 3/8 + (- 10) = - 11 3/8