Pick the closest whole number to 8.6 that is not a fraction. In this case it is 9.
9000
10000000
100
It is 0 0.00005
To express 961 to one significant figure, you round it to the nearest significant digit. The first significant digit in 961 is 9, and since the next digit (6) is 5 or greater, you round up. Therefore, 961 rounded to one significant figure is 1000.
It's already there.
7000
0.1
2,000,000
10000000
9000
It is 0.01
0.9
12
800
100
200