The second number after the decimal is the hundredths place. To round to that place, you look at the number after it. In this case 6 is the hundredths place and 5 is the number after it. If the number after it is 5 or higher, the hundredths place number increases by 1, if it is less than 5 the hundredths place number doesn't change. So the answer is 8.47.
It is 8.47 because the number in the hundredths is 6. So, you go to the right of the 6 and you see a 5. The rule is that if the number to the right is higher then 5 then the number you are rounding goes up one and the rest to the right turn to zeros. If the number to the right is less then 5, the number you are rounding stays the same and the other numbers to the right turn to zeros.
