How to Use a Number Line

PDF download Download Article
PDF download Download Article

A number line is a line drawing where numbers are written from smallest to largest. A number line can be a tool to do simple math problems. This is most helpful for doing problems with small numbers. If your math problem involves numbers over 20 or fractions, it might get a bit too hard to use this tool. It is easiest to use a number line to help you add and subtract small numbers. You can also use it to do problems with negative numbers. [1]

Method 1
Method 1 of 6:

Setting Up a Number Line

PDF download Download Article
  1. This will be the base of your number line. [2]
    • You can draw this in pen or marker, if you want to use your number line over and over again.
  2. This will make it look like a train track.
    • You can also make these in pen so you can use the number line for more than one problem.
    Advertisement
  3. Start with zero above the first hashmark on the left. [3]
    • At each hashmark, write the next number up. For example, above the hash mark next to zero, write 1.
    • You can write these in pen as well, so you can re-use the number line over and over again.
  4. Remember, doing math problems with numbers over 20 will make this method too hard.
    • Now your number line should read from 0 to 20, going from left to right.
    5. Advertisement
Method 2
Method 2 of 6:

Adding Using a Number Line

PDF download Download Article
  1. Determine which number is first in the problem and which is second. [4]
    • For example, in 5 + 3, the first number is 5 and the second number is 3.
  2. Put your finger there.
    • This is where you will start counting.
    • For example if your math problem is 5 + 3, you should put your finger on 5 on your number line.
  3. You have now moved 1 space.
    • If you start at 5, when you reach 6, you have moved 1 space.
  4. This will make sure you end on the answer to your problem. [5]
    • Don't move more spaces than the second number in your addition problem.
    • For example, if the second number in your problem is 3, you will move 3 spaces.
  5. That is the answer to your math problem. [6]
    • For example, if your math problem was 5 + 3, you would have moved 3 spaces to the right of 5. Your finger would be on 8 on your number line. 5 + 3 = 8.
  6. This will help you make sure you have the right answer to your math problem.
    • If you come up with a different answer during your check, try again to double check.
    7. Advertisement
Method 3
Method 3 of 6:

Subtracting Using a Number Line

PDF download Download Article
  1. Find which number is the first number in the problem and which is second.
    • In the problem 7 - 2, 7 is the first number in the problem and 2 is the second number in the problem.
  2. Put your finger there.
    • If your math problem was 7 - 2, you would start by putting your finger on 7 on your number line.
  3. You have now moved 1 space.
    • For example: if you start at 7, when you reach 6, you've traveled 1 space.
  4. This will make sure you end on the answer to your problem. [7]
    • If the second number in your problem is 2, you should have moved your finger to the left two spaces.
  5. That is the answer to your subtraction problem.
    • For example, in the problem 7 - 2, you would have started your problem at 7 on your number line. You would have moved 2 positions to the left, ending with your finger on 5 on your number line. 7 - 2 = 5.
  6. This is to check your answer.
    • If you get a different result from your check, try again to see where you made a mistake.
    7. Advertisement
Method 4
Method 4 of 6:

Making a Number Line with Negative Numbers

PDF download Download Article
  1. Start by making a long horizontal line on a piece of paper.
    • This will be the base of your number line.
  2. This will make your line look like a train track.
    • You will need to make more hashmarks on the line than for a simple addition/subtraction problem if you are working with negative numbers.
  3. Put zero on the hashmark in the center of your line. [8]
    • Put 1 to the right of zero and -1 to the left of zero. -2 will go to the left of -1 and so on.
  4. Zero should be in the middle.
    • Try numbering up to 20 on the right and -20 on the left.
    5. Advertisement
Method 5
Method 5 of 6:

Adding With Negative Numbers

PDF download Download Article
  1. Find the first and second numbers in the problem.
    • For example, in 6 + (-2), 6 would be the first number and -2 would be the second.
  2. Put it on the first number in your problem.
    • In 6 + (-2) you would start by putting your finger on 6 on your number line.
  3. Adding a negative number is very similar to regular subtraction. You have now moved 1 space. [9]
  4. This will make sure you end on the answer to your problem. [10]
    • For example, if the second number in your problem is -2, you should have moved your finger to the left 2 spaces.
  5. This is the answer to your addition problem. [11]
    • For example, if your problem was 6 + (-2), you would have started with your finger on 6. You would have moved your finger to the left two spaces, ending on 4. 6 + (-2) = 4.
  6. This is to check your answer.
    • If you get an answer when you check your problem, try again to see where you made your mistake.
    7. Advertisement
Method 6
Method 6 of 6:

Subtracting with Negative Numbers

PDF download Download Article
  1. You will need numbers less than zero and more than zero.
    • Remember, on your negative number line zero will be in the middle. All the negative numbers will be to the left of zero and all the positive numbers will be to the right of zero.
  2. Find what number is first and which is second in the problem. [12]
    • For example, in (-8) - (-3), the first number is -8 and the second is -3.
  3. This is where you will start.
    • If your problem was (-8) - (-3), you would put your finger on -8 on your number line.
  4. Subtracting a negative number is much like addition with regular numbers.
    • If you started on -8, you should now be on -7. You will have moved one space.
  5. This will make sure you end on the answer of your problem.
    • For example, if the second number in the problem is -3, you should have only moved 3 spaces on your number line.
  6. That number is the answer to your subtraction problem.
    • For example, in the problem (-8) - (-3), you would have started with your finger on -8 and would have moved 3 spaces to the right, ending on -5. (-8) - (-3) = -5.
  7. This is to check your answer.
    • If you don't get the same answer this time, try again to see where you made a mistake.
    • In a test, they always give you something for a reason. When they ask you something, it's for a specific chapter test.
    • Think why some information is there and which specific section it is associated with.
    • For example, you may be given a word problem about the line of sight, and the chapter may be on trigonometry.
    8. Advertisement

What Tools Can You Use To Learn Math?


Community Q&A

Search
Add New Question
  • Question
    Using the number lines. 209-159, what do I do?
    Donagan
    Top Answerer
    Start at +209, then move 159 to the left.
    Thanks! We're glad this was helpful.
    Thank you for your feedback.
    If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
    Yes No
    Not Helpful 14 Helpful 10
  • Question
    How do I plot 6 - (-2) on a number line?
    Donagan
    Top Answerer
    Start at +6, then move 2 to the right.
    Thanks! We're glad this was helpful.
    Thank you for your feedback.
    If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
    Yes No
    Not Helpful 15 Helpful 7
  • Question
    How do I divide on a number line?
    Donagan
    Top Answerer
    Here's a very simple example of how to do that: Let's say we're dividing 2 into 6. Begin with the section of the number line from zero to 6. Count two units from zero to 2. Count another two units from 2 to 4. Count another two units from 4 to 6. So we have found that a length of two units exactly fits inside the length of six units three times. Thus, 2 divides into 6 three times.
    Thanks! We're glad this was helpful.
    Thank you for your feedback.
    If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
    Yes No
    Not Helpful 7 Helpful 6
See more answers
Ask a Question
200 characters left
Include your email address to get a message when this question is answered.
Submit
      Advertisement

      Video

      Tips

      Submit a Tip
      All tip submissions are carefully reviewed before being published
      Name
      Please provide your name and last initial
      Submit
      Thanks for submitting a tip for review!
      Advertisement

      You Might Also Like

      How to
      Divide and Multiply by Negative Numbers
      How to
      Subtract
      How to
      Add
      How to
      Solve Exponents
      The Best Tips & Tricks to Help You Get Better at Math
      How to
      Do Math Proofs
      How to
      Use an Abacus
      How to
      Calculate Percentages
      The Trachtenberg Method: Learn to Calculate Multi-Digit Numbers Quickly
      How to
      Measure Centimeters
      How to
      Calculate Ratios
      How to
      Use the Percent Change Formula
      How to
      Calculate Percentage Increase
      How to
      Find the Y Intercept
      Advertisement

      References

      1. ↑ https://www.splashmath.com/math-vocabulary/number-sense/number-line
      2. ↑ https://www.cuemath.com/numbers/number-line/
      3. ↑ https://www.mathsisfun.com/number-line.html
      4. ↑ https://www.khanacademy.org/math/arithmetic/arith-review-add-subtract/arith-review-strategies-for-adding-within-100/v/correct-number-lines-for-addition-and-subtraction
      5. ↑ https://www.khanacademy.org/math/cc-third-grade-math/imp-addition-and-subtraction/imp-strategies-for-adding-two-and-three-digit-numbers/v/exercise-for-numberline-addition-and-subtraction
      6. ↑ https://www.khanacademy.org/math/arithmetic/arith-review-add-subtract/arith-review-strategies-for-adding-within-100/v/correct-number-lines-for-addition-and-subtraction
      7. ↑ https://www.khanacademy.org/math/cc-third-grade-math/imp-addition-and-subtraction/imp-strategies-for-adding-two-and-three-digit-numbers/v/exercise-for-numberline-addition-and-subtraction
      8. ↑ https://www.splashmath.com/math-vocabulary/number-sense/number-line
      9. ↑ https://www.splashmath.com/math-vocabulary/number-sense/number-line
      1. ↑ https://www.khanacademy.org/math/cc-seventh-grade-math/cc-7th-negative-numbers-add-and-subtract/cc-7th-add-sub-neg-number-line/v/adding-negative-numbers-on-number-line-examples
      2. ↑ https://www.khanacademy.org/math/cc-seventh-grade-math/cc-7th-negative-numbers-add-and-subtract/cc-7th-add-sub-neg-number-line/v/adding-negative-numbers-on-number-line-examples
      3. ↑ https://www.khanacademy.org/math/cc-seventh-grade-math/cc-7th-negative-numbers-add-and-subtract/cc-7th-sub-neg-intro/a/subtracting-negative-numbers-review

      About This Article

      In other languages
      Thanks to all authors for creating a page that has been read 149,614 times.

      Reader Success Stories

      • Dutchess Chellie

        Sep 14, 2017

        "Gave the basic steps of setting up the number and how to work out the problem."
      More reader stories Hide reader stories
      Share your story

      Did this article help you?

      Advertisement