How do you use millimeters to round to the nearest centimeter?

Answer 1

If the last two digits of your number expressed in mm is 50 or higher, round up. If 49 or lower, round down.

Answer 2

To round millimeters to the nearest centimeter, divide the millimeters by 10 to convert them to centimeters. Then round the centimeter value to the nearest whole number. If the remainder after division is 5 or more, round up; if it's less than 5, round down.