On a miter saw, when you're cutting a 90 degree cut, the miter saw reads zero. On a protractor, it reads 90. So it's an unending source of confusion for people. RON HAZELTON: So Mark, show me how it works.
A ruler is used to measure units of length, inches, feet and yards. Standard rulers have inches on one side and centimeters on the other. A typical ruler measures up to 12 inches, and is equivalent to 30.48 centimeters. This is also equivalent to 1 foot. Each inch on a ruler has markings in between that are a fraction of an inch.
Here is a quick little Ruler Measurements Reading video I found on youtube. I think it might help you if you are having a great deal of trouble understanding. Enjoy! How to understand reading a ruler and ruler measurements and what all those marks on the ruler are all about is just a matter of going over the material again. Once you realize that all the marks on the ruler means something different you will be measuring with the best of them!