# What is a Number Line? Number Line

A number line is a visual representation of numbers along a horizontal line. Learn more about number lines, their usefulness, and how to teach with them.

What is a Number Line?

In math, a number line is a horizontal straight line with numbers placed at equal distances from each other along that line. Some will have a specified starting and ending point. These are called closed number lines. Number lines can also be blank or empty.

A vertical number line is called a number ladder.

Number lines are typically introduced in kindergarten and are used frequently throughout elementary and middle school to help build skills like counting, adding, and subtracting numbers.

Why is a Number Line useful for my lessons?

A number line is helpful because it acts as a visual math aid.

It can support teachers and parents as they teach children how to count and write numbers. It’s also a tool that can help build understanding behind adding, subtracting, multiplying, and dividing numbers. And it’s a handy way to show how fractions make up a whole!

In addition, blank or empty number lines can be used alongside word problems to aid students as they take “jumps” to work towards the solutions.

Here are a few fundamental rules to keep in mind when using number lines:

• Numbers increase when moving left to right and decrease when moving right to left. They are always in sequential order.
• Numbers are spaced evenly on a line to show that the value between the intervals is the same.
• Positive and negative numbers, fractions, and decimals can be included.
• To add, move to the left.
• To subtract, move to the right.
• To multiply, skip-count in groups to the left.
• And to divide, skip-count in groups to the right.

Number lines are also obvious to read. While it’s not a ruler, and the space between numbers isn’t set, the values included help children visualize and compare the relationships between the numbers shown on the line. This, in turn, helps develop number sense.

Overall, they are versatile math tools that can be used in the classroom and at home.