A number is a number, you do not "do" numbers. There are things which you can do to it or with it but in order to answer that Iyou need to say what you want to do.
015 = 15
I write 6 015 103 as 6 015 103.
Since 015 = 15, 015 of 1% = 15 of 1% = 15% or 0.15
015% = 15% is equal to 0.15
0.015
.015 as a fraction is 15/1000. In simplified form it is 3/200.
.015
1.5%
999
It is 150 ml.
.015
15/1000