710 as a decimal is the same as 710.0
You have already expressed it as a decimal.
6 + 710 = 716
7/10 = 0.7
710
7.10 = 710%
7.10 = 710%
1710.0
7/10 = 0.7
710
If you mean 2 and 7/10 then as a decimal it is 2.7
It is 710, as in the question. There is no need to add a decimal point. Adding a decimal point and one or more 0s is wrong because that implies a degree of precision that cannot be justified.