Round off 8.5678 to nearest thousandth
8.57
You rounded it to the nearest hundredth.
Check this place value chart.
http://www.learn-with-math-games.com/decimal-place-value-chart.html
To round off a number to the nearest thousandth, you need to look at the digit in the fourth decimal place (the thousandth place) and determine whether to round up or down based on the digit in the fifth decimal place.
In this case, the number is 8.5678. The digit in the fourth decimal place is 6, and the digit in the fifth decimal place is 7. Since 7 is 5 or greater, we round up.
To round up, increase the digit in the fourth decimal place by 1. Therefore, the number rounded to the nearest thousandth will be 8.568.