Understanding Number Lines in Mathematics

Study Notes

To create a number line, draw a straight horizontal line with arrows on both ends, then add equidistant notches intersecting the line at a 90-degree angle.
A standard number line usually has the origin in the middle, with positive integers to the right and negative integers to the left.
Number lines can count by twos, fives, or any other constant.
Find numbers not explicitly shown on the number line by marking a coordinate in between two existing coordinates.
Number lines can be used to model addition and subtraction by counting to the left for subtraction or right for addition.
The rules for adding and subtracting negative numbers on a number line are the opposite of those for positive numbers: when a negative number is added, move to the left; when a negative number is subtracted, move to the right.
Multiplication on a number line can be visualized as adding one factor to itself as many times as indicated by the second factor.
Division can be represented on a number line by counting the number of times one number fits into another.
Intervals on a number line are sets of numbers expressed as inequalities. To represent intervals on a number line, draw an open circle for less than or greater than, and a shaded circle for less than or equal to or greater than or equal to. A bolded number line represents the range of the interval.

Description

Learn about number lines and how they are used to solve basic arithmetic problems like addition, subtraction, multiplication, and division. Understand how numbers are placed on notches that are equally distant from each other on the number line.