How do you write 300 thousandth as a decimal?

To write 300 thousandth as a decimal, you need to place the decimal point three places to the left of the last digit. In this case, the last digit is 0, so you would place the decimal point after the 0 to get 0.0003. This is because each place value to the right of the decimal point represents a power of 10, so moving three places to the left indicates a value of 10^-3 or 1/1000.