6.31 rounded to the nearest tenth is 6.3. When rounding, you look at the digit in the hundredths place (which is 1 in this case). Since 1 is less than 5, you do not round up, and the tenths place remains 3.
174.3
1.965 rounded to the nearest tenth is 2.0
7.1
236.6
1.2
0.4
18.2
8.1
31.8
20.1
It is: 58.1
10.0