# Ruler - Definition with Examples

**What is a ruler?**

Rulers can be used to measure lengths in both metric and customary units. Here, the ruler is marked in centimeters (cms) along the top and in inches along the bottom.

The marks or intervals on a ruler are called hash marks.

**Measuring Objects using a Ruler:**

Here, the shoelace is 17.6cms long in metric units of length, and 7 inches long in customary units of length.

**Reading a Ruler:**

10-millimeter hash marks make 1 centimeter.

Reading Inches: An inch is bigger than a centimeter. The big long hash marks above which numbers are written on the opposite side of the centimeter ruler denote inches.

## Let's sing!

*Draw a long straight line,*

*Or measure the length of a vine.*

*All you need to do is align,*

*The ruler is a tool so fine!*

## Let's do it!

## Related math vocabulary

The Complete K-5 Math Learning Program Built for Your Child