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How Do You Write an Inequality from a Number Line Graph?

Write an inequality for the graph below

Summary

  1. Look for any circles on the number line
  2. There is an open circle at 4
  3. Look at what direction the arrow is pointing
  4. The arrow is pointing left
  5. 'n' is our variable
  6. "<" means "less than"
  7. We use a less than symbol because we had a left-pointing arrow
  8. Our open circle was at 4
  9. So our inequality is: n is less than 4

Notes

    1. 'n' will be the variable for our inequality
    1. This means 4 will NOT be included in our inequality
    1. The numbers covered by the arrow are the numbers included in the inequality
    2. So if the arrow points left, it covers all the numbers LESS THAN the number it starts from
    3. "Less than" is represented by the "<" symbol
    1. The numbers covered by the arrow are the numbers included in the inequality
    2. So if the arrow points right, it covers all the numbers GREATER THAN the number it starts from
    3. "Greater than" is represented by the ">" symbol
    1. Left pointing arrows mean "less than" inequalities
    1. Notice how the "<" symbol looks like an arrow pointing to the left
    2. That's pretty easy to remember!
    1. Notice how the ">" symbol looks like an arrow pointing to the right
    2. That's pretty easy to remember!
    1. Remember, our variable was 'n'
    1. Remember, the "<" symbol looks like a left-pointing arrow
    1. This means we will have a less than symbol, not a less than or equal to symbol
    1. Since we had an OPEN we will have a less than symbol, not a less than or equal to symbol
    1. Look back at the number line
    2. Our open circle was at 4
    1. This inequality reads: "n is less than 4"
    2. The arrow on the graph covers everything less than 4