1. Вычисли. 40 + 5 =; 64 − 4 =; 80 + 7 =; 67 − 7 =; 30 + 6 =; 33 − 3 =; 10 + 2 =; 91 − 1 =; 50 + 9 =; 38 − 8 =; 40 + 5 =; 74 − 4 =; 70 + 7 =; 28 − 8 =; 20 + 6 =; 24 − 4 =; 90 + 7 =; 68 − 8 =; 50 + 3 =; 42 − 2 =; 90 + 3 =.

Выполним сложение и вычитание единиц.

40 + 5 = 45; 64 − 4 = 60; 80 + 7 = 87.

67 − 7 = 60; 30 + 6 = 36; 33 − 3 = 30.

10 + 2 = 12; 91 − 1 = 90; 50 + 9 = 59.

38 − 8 = 30; 40 + 5 = 45; 74 − 4 = 70.

70 + 7 = 77; 28 − 8 = 20; 20 + 6 = 26.

24 − 4 = 20; 90 + 7 = 97; 68 − 8 = 60.

50 + 3 = 53; 42 − 2 = 40; 90 + 3 = 93.

Ответ: 45, 60, 87; 60, 36, 30; 12, 90, 59; 30, 45, 70; 77, 20, 26; 20, 97, 60; 53, 40, 93.