How do you write two hundred and fifteen thousandths in decimal form?

To write two hundred and fifteen thousandths in decimal form, you would write it as 0.215. This is because each place value after the decimal point represents a power of 10 that is a negative exponent. In this case, the digit '2' is in the tenths place (10^-1), the digit '1' is in the hundredths place (10^-2), and the digit '5' is in the thousandths place (10^-3).