Ответ:
Вычислим значение выражений:
2) -2/3 + 13/15 = (-2 * 5 + 13)/15 = (-10 + 13)/15 = 3/15 = 1/5;
3) 13/16 + (-9/32) = (13 * 2 — 9)/32 = (26 — 9)/32 = 17/32;
4) -4 5/9 + (-7 1/6) = -4 — 7 — 5/9 — 1/6 = -11 — (10 + 3)/18 = -11 13/18;
5) -5 7/8 + (-6 3/10) = -11 — 7/8 — 3/10 = -11 — (35 + 12)/40 = -12 7/40;
6) -5 13/18 + 12 11/12 = 7 + 11/12 — 13/18 = 7 + (33 — 26)/36 = 7 7/36;
7) -13 + 7 3/16 = -6 + 3/16 = -5 13/16;
8) -2 3/8 + (-1 5/9) = -3 — 3/8 — 5/9 = -3 — (27 + 40)/72 = -3 67/72;
9) -8 + 4 5/22 = -4 + 5/22 = -3 17/22;
10) -2 9/20 + 5 7/30 = 3 + 7/30 — 9/20 = 3 + (14 — 27)/30 = 3 — 13/30 = 2 17/30;
11) -5 1/4 + 1 3/8 = -5 2/8 + 1 3/8 = -4 + 1/8 = -3 7/8;
12) 4 3/7 + (-8 9/14) = -4 + 3/7 — 9/14 = -4 + 6/14 — 9/14 = -4 — 3/14 = — 4 3/14.