Ruler

A ruler is a simple tool that helps us measure how long something is. It's like a straight stick with marks on it that show us how many inches, centimeters, or other units there are.

When we want to measure something, we can place the ruler next to it and line it up with one end. Then we can look at the marks on the ruler to see how long it is.

For example, if we want to measure a piece of paper, we can use a ruler to see how many inches or centimeters long and wide it is. Using a ruler helps us accurately measure things, which is important in many situations, such as when building or creating things.