Ответ:
Вычислим примеры по порядку:
7 + 8 = 15; 9 + 6 = 15; 8 + 5 = 13; 7 + 6 = 13.
16 − 4 = 12; 19 − 6 = 13; 13 + 5 = 18; 12 + 7 = 19.
13 − 5 = 8; 15 − 9 = 6; 14 − 6 = 8; 12 − 7 = 5.
20 − 1 = 19; 39 + 1 = 40; 60 − 1 = 59; 99 + 1 = 100.
40 + 9 = 49; 52 − 2 = 50; 37 − 30 = 7; 80 + 20 = 100.
70 − 30 = 40; 80 − 50 = 30; 40 + 60 = 100; 60 + 20 = 80.
