How to Graph Points on a Number Line

Number lines are used at various levels of mathematics instruction. In early elementary grades, number lines include only zero and positive integers, and can be used to teach basic addition. When students learn subtraction and negative numbers, number lines can be extended to include those. Then when students learn division, fractions can be included; and when students learn roots (fractional exponents), then irrational numbers can be added as well. Finally, in the later elementary grades, when students learn to graph equations, a solid understanding of number lines is vital, as the coordinate system is based on two perpendicular number lines.

• 1

  Ensure the number you need to plot is within the bounds of the number line. For instance, if your number line goes from -3 to +3 and you have the number +4, you will not be able to plot it.

• 2

  Determine if your number is positive or negative. Negative numbers go to the left of zero, positive numbers go to the right of zero.

• 3

  Determine if your number is an integer or fraction.

• 4

  Plot integers by plotting a point on the line that corresponds to that integer. For example, if you have to plot +4, put a point over the +4 line.

• 5

  Plot fractions by using a ruler to measure between the lower and higher integers, and then dividing the distance by the number of inches, and multiplying by the fraction. For example, if your number is 1 1/4 and the distance between 1 and 2 is 2 inches, then plot a point 1/4*2 = 1/2 inches past 1.