How do you write a measure as a decimal to the nearest thousandth?

Sometimes it is advantageous to express a value in round numbers. To round to a particular place, look at the digit immediately to the right of the one you want to round to, in this case, the ten thousandths place. If that digit is 4, 3, 2, 1 or 0, zero it and everything to the right of it out. If that digit is 5, 6, 7, 8 or 9, increase your target digit by one and zero everything to the right of it out. If your target digit is 9, it will become a zero and increase the digit to the left of it by one.