6. 408-270+21008:808 71370:234+695.50 280084:28-125.8 (327+541350:450):3 (31460+1040):(150-2400) (78213-75209).207-45 (992341:269+780)-325 434280:517.306+2744

Решение:

1. \( 408 - 270 + 21008 : 808 = 138 + 26 = 164 \)

2. \( 71370 : 234 + 695.50 = 305 + 695.50 = 1000.50 \)

3. \( 280084 : 28 - 125.8 = 10003 - 125.8 = 9877.2 \)

4. \( (327 + 541350 : 450) : 3 = (327 + 1203) : 3 = 1530 : 3 = 510 \)

5. \( (31460 + 1040) : (150 - 2400) = 32500 : (-2250) = -14.44 \)

6. \( (78213 - 75209) \cdot 207 - 45 = 3004 \cdot 207 - 45 = 621828 - 45 = 621783 \)

7. \( (992341 : 269 + 780) - 325 = (3689 + 780) - 325 = 4469 - 325 = 4144 \)

8. \( 434280 : 517 \cdot 306 + 2744 \)

8.1. \( 434280 : 517 \approx 840.04 \)

8.2. \( 840.04 \cdot 306 + 2744 = 257052.24 + 2744 = 259796.24 \)