A decimal number is simply a way of representing a number in such a way that the place value of each digit is ten times that of the digit to its right. If it does not contain a fractional part then the decimal representation does not require a decimal point. So the decimal for 173 is 173 – as in the question.
0.125.
0.085
0.875
.12
75%
It is simply: 65.0
0.24
0.5625
0.7171
3/10 = 0.3
15% = 0.15
0.07