Recall that number lines can be horizontal or vertical. This lesson focuses on horizontal number lines. Remember that horizontal number lines are straight, flat lines that generally have the number 0 in the middle. The numbers to the left of 0 are negative, and the numbers to the right of 0 are positive. The negative integers decrease as you move further left of 0. The positive integers increase as you move further right of 0. The image below illustrates a horizontal number line.
A horizontal number line from −5 to 5 in increments of 1.
You can plot integers along a horizontal number line.
For Example
Noor purchased two balloon arches for the school dance.
Plot the integer 2 on a horizontal number line.
To plot the integer 2 on a horizontal number line, you must first create the line! Review how to create a horizontal number line and plot integers along it by clicking through the slides below. This skill will be very helpful throughout the rest of this lesson.
A horizontal number line with 0 marked in the middle.
Draw a horizontal line with arrows on each end, and identify 0 (most of the time it is in the middle of the line).
A horizontal number line from \( 0 \) to 5 in increments of 1.
Write increasing positive integers to the right of 0. Make sure the spacing between the hashmarks is equal.
A horizontal number line from −5 to 5 in increments of 1.
Write decreasing negative integers to the left of 0. Make sure the spacing between the hashmarks is equal.
Question
Look at the horizontal number line above. What is the largest integer on the number line? What is the smallest? Explain your reasoning.
The largest integer is 5. This integer is the largest because it is furthest to the right on the number line. The smallest integer is −5. It is the smallest because it is furthest to the left on the number line.
A horizontal number line from −5 to 5 in increments of 1. There is a point plotted on the integer 2.
Now you can plot the integer 2 on your horizontal number line.
The integer 2 is plotted along this number line with a closed dot. It is 2 units to the right (in the positive direction) of 0.
Drawing a number line is simple and can be very useful when ordering and comparing integers as well as conducting other operations with integers.
Let's Practice
Practice your integer plotting skills with the activity below. Read the question on the front of each box. Once you think you know the answer, click the box to check your response.
Plot the integers 3 and −3 on a horizontal number line.
The integers 3 and −3 are plotted on the number line shown. The integer −3 is three units to the left of 0. The integer 3 is 3 units to the right of 0. When integers are the same distance from 0, they are opposites.
A horizontal number line from −5 to 5 in increments of 1. There are two points plotted; one at −3 and one at 3.
Noor's committee overspent the table decorations budget by $5. You can represent this integer as −$5.
Plot the integer −5 on a horizontal number line.
The integer −5 is 5 units to the left of 0.
A horizontal number line from −5 to 5 in increments of 1. There is a point plotted on the integer −5.
What integer is plotted on this number line?
A horizontal number line from −5 to 5 in increments of 1. There is a point plotted on the integer 1.
1
The plotted integer is 1 unit to the right of 0. This number is 1.
What integer is plotted on this number line?
A horizontal number line from \( - 20 \) to 5 in increments of 1. There is a point plotted on the integer \( - 18 \).
−18
The marked point on the number line is 18 units to the left of 0.
