19. Найди значение выражения. 67 + 48 + 12 67 – 48 + 12 67 – 48 – 12 20 . 5 + 2 20 . 5 . 2 20 : 5 . 2 84 : 2 : 2 30 . 7 + 20 . 5 23 . 10 . 3

1. $$67 + 48 + 12 = 67 + (48 + 12) = 67 + 60 = 127$$
2. $$67 - 48 + 12 = (67 - 48) + 12 = 19 + 12 = 31$$
3. $$67 - 48 - 12 = (67 - 48) - 12 = 19 - 12 = 7$$
4. $$20 \cdot 5 + 2 = 100 + 2 = 102$$
5. $$20 \cdot 5 \cdot 2 = 100 \cdot 2 = 200$$
6. $$20 : 5 \cdot 2 = 4 \cdot 2 = 8$$
7. $$84 : 2 : 2 = 42 : 2 = 21$$
8. $$30 \cdot 7 + 20 \cdot 5 = 210 + 100 = 310$$
9. $$23 \cdot 10 \cdot 3 = 230 \cdot 3 = 690$$

Ответ: 1) 127, 2) 31, 3) 7, 4) 102, 5) 200, 6) 8, 7) 21, 8) 310, 9) 690