Assuming you mean (eleven thousand-five hundred three) thousandths, that the same as 11503 / 1000 = 11.503 If you actually meant eleven thousand-five hundred AND three thousandths, that would be 11500.003
The way ou would write six thousand two hundred and three hundred eleven hundred thousandths is 6200.311
You write it as 11,500.003
Eleven and twenty-three thousand, four hundred six hundred-thousandths.
Eleven and twenty-three thousand, four hundred six hundred-thousandths.
Three hundred eleven and three thousand, six hundred eighty-five ten-thousandths.
Eleven and twenty-three thousand, four hundred six hundred-thousandths.
Eleven thousand, four hundred twenty-two and fifty-three thousandths.
Eleven and three thousand, one hundred thirty-two ten-thousandths.
You cannot write it as it appears.
115300
Fourteen thousand nine hundred three and five hundred six thousandths is 14,903.506