This depends what you are rounding to. If you are rounding to the nearest whole number it would be 8. If you are rounding to the nearest tens place it would be 10.
The answer depends on the degree of rounding. To the nearest ten, the answer is 10; to the nearest 100 it is 0.
800
800
1 x 809, 809 x 1
1 and 809
30096 + 809 = 30905
809
As 839 is less than 850 you round it down to 800
C/119-214=809
809 multiplied by 17 is 13,753.
67 x 809 = 54,203
62.2308
809 x 90 = 72810