2. Реши примеры. (40-20) + (7-4) = (90-30) + (5-3) = (50-40) + (3-1) = (20-10) + (8-6) = (80-50) + (6-2) = (60-30) + (4-3) = (30-20) + (9-7) =

Решение:

1. \( (40-20)+(7-4) = 20 + 3 = 23 \)
2. \( (90-30)+(5-3) = 60 + 2 = 62 \)
3. \( (50-40)+(3-1) = 10 + 2 = 12 \)
4. \( (20-10)+(8-6) = 10 + 2 = 12 \)
5. \( (80-50)+(6-2) = 30 + 4 = 34 \)
6. \( (60-30)+(4-3) = 30 + 1 = 31 \)
7. \( (30-20)+(9-7) = 10 + 2 = 12 \)

Ответ: 23, 62, 12, 12, 34, 31, 12.