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Comparing decimal numbers on a number line

Sal compares decimals on a number line. Created by Sal Khan and Monterey Institute for Technology and Education.

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  • starky tree style avatar for user ELI(jack frost)
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    nice
    (31 votes)
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  • starky ultimate style avatar for user edwin R
    why would we need them in a line
    (11 votes)
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    • male robot johnny style avatar for user (ง'̀-'́)ง
      Hi, Edwin!

      Just like how you count 1 to 2 to 3 to 4, we are also increasing our values as we go right and decrease them as we go down.

      The number line is to help us evaluate the location of a number or fraction on a scale. it is also a pointer that if we add, subtract, multiple, or divide said numbers into each other, where they would end up or be on said number line.

      It's not crucial to use a number line in order to do these problems. the number line is mostly a visual representation and a helpful reminder for people who have trouble spotting where their numbers should be.

      Thank you so much for the question! have a nice day! :)
      (8 votes)
  • blobby green style avatar for user coleb21
    he said lumber line it's ok though
    (14 votes)
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  • duskpin ultimate style avatar for user Brooke M
    i keep getting them wrong. can you please explain this more clearly?
    (5 votes)
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  • winston default style avatar for user Caleb Brock
    so are decibels just negative numbers right? ps. sorry for bad grammar
    (5 votes)
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  • cacteye purple style avatar for user Jailah Rushing
    why is he saying "10ths" when it is 11
    (4 votes)
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  • male robot johnny style avatar for user OneTouch
    i understand this problem very much
    (3 votes)
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  • aqualine ultimate style avatar for user kfkjhnshmgfmdmnfzdmmgnmk
    bro really said lumber line
    (2 votes)
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  • piceratops tree style avatar for user Aries
    im confused can you show another strategy if there is one?
    (2 votes)
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  • purple pi purple style avatar for user Maria
    Can you make a fraction number line, too? How would you do that?
    (1 vote)
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Video transcript

Use a number line to compare 11.5 and 11.7. So let's draw a number line here. And I'm going to focus between 11 and 12, because that's where our two numbers are sitting. They're 11, and then something else, some number of 10ths. So this right here is 11. And this right here would be 12. And then let me draw the 10ths. So this would be smack dab in between. So that would be 11 and 5/10, or that would be 11.5. Well, I've already done the first part. I've figured out where 11.5 is. It's smack dab in between 11 and 12. It's 11 and 5/10. But let me find everything else. Let me mark everything else on this number line. So that's 1/10, 2/10, 3/10, 4/10, 5/10, 6/10, 7/10, 8/10, 9/10, and then 10/10, right on the 12. It's not completely drawn to scale. I'm hand-drawing it as good as I can. So where is 11.7 going to be? Well, this is 11.5, this is 11.6, this is 11.7. 11 and 7/10. 1/10, 2/10, 3/10, 4/10, 5/10, 6/10, 7/10. This is 11.7. And the way we've drawn our number line, we are increasing as we go to the right. 11.7 is to the right of 11.5. It's clearly greater than 11.5. 11.7 is greater than 11.5. And really, seriously, you didn't have to draw a number line to figure that out. They're both 11 and something else. This is 11 and 5/10. This is 11 and 7/10. So clearly, this one is going to be greater. You both have 11, but this has 7/10, as opposed to 5/10.