In order to round to the nearest hundreth,, we must look at the second number behind the decimal. If this number is smaller than 5 then we round down,, but if it is 5 or larger then we round up. Looking at the second number from the decimal point,, you can see that it is smaller than 5. This means that we round down to make our final answer 12.8.
Let me know if you have any further questions.
:)