I would write 15,001 as fifteen-thousand and one. Though I suspect the hyphen is not necessarily correct.
It would be 1500 pounds.
30.15
15.069
Fifteen millionths
Not sure about thrids but there are 3 thirds in one.
When you write a check in pesos, you write out the amount. You can write fifteen thousand pesos under the payee. On the right, you write out 15,000.
You would write is either.. 115,000 or 115 000
0.0015
15.1
Fifteen in Chinese would be 十五
fifteen ten thousandths