71.8
71.841:
The 4 represents the number that we'll be looking at since 4 is the next position to the right of 8, 8 is in the Tenths place. 4 is in the Hundredths place, and 4 will be the only number that could round up the 8.
In order to round, we need to remember how to round numbers:
First, 4<5, meaning that 4 is less than 5.
#1 above is stating that the number to the left of 4 stays the same.
If we use that rule:
71.8 is our answer.
