Answer :

The saying is "Five or above, give it a shove. Four or below, let it go" Meaning, round up if the following number is ≥5, and to round down if the number is ≤4
In this case, 80.945 would be rounded to 80.9.
Hope this helps!
Tenth is the first number after decimal. If the number after tenths is 5 +, the number will be rounded up. If 4 or below, the number will stay the same..

80.945

The number after tenths is below 5, so it's going to stay the same..

80.945 rounded to the nearest tenth is 80.9