In the United States, the standard way would be 10:15 A.M., or alternatively 10:15 a.m., 10:15 AM, or 10:15a.
However, in some other parts of the world, you would write 10.15 a.m., using a period instead of a colon.
0.0015
8.0015
15010
Ten and fifteen thousandths.
6,000.0015
1.0015
15/10000 or 0.0015
510,015
Fifteen and five ten-thousandths.
fifteen ten thousandths
0.0015
It is 15,210,000