Millimeters

The ruler

The ruler is 12 inches and about 36 centimeters long.

The little lines in between the centimeters are called millimeters. There are ten millimeters in a centimeter.

Centimeters side

Inches side

On a ruler there is a centimeters side and a inches side. For metric you would use the centimeter side. Centimeters are smaller than inches. There are about three centimeters in an inch.

On the ruler there are an inch side. For customary you would use the inches.

Ruler