Решение:
- \( 800 : 2 + 50 = 400 + 50 = 450 \)
- \( 300 \cdot 3 + 40 = 900 + 40 = 940 \)
- \( 470 - 200 \cdot 2 = 470 - 400 = 70 \)
- \( 910 - 400 : 2 = 910 - 200 = 710 \)
- \( 600 : 3 + 90 = 200 + 90 = 290 \)
- \( 800 : 2 + 50 = 400 + 50 = 450 \)
Ответ: 450, 940, 70, 710, 290, 450.