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Adding mixed numbers: 19 3/18 + 18 2/3

To add two mixed numbers, you can separate the whole number and fraction parts. Add the whole numbers together as you normally would, and then find a common denominator to add the fractions. Once you have your sum, you may need to simplify the fraction for your final answer. Created by Sal Khan.

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  • aqualine tree style avatar for user Alfire
    I don't get this. Help!
    (7 votes)
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  • piceratops seed style avatar for user Yuri Costa
    Why can't I convert the mixed numbers into improper fractions and then add them together?
    (0 votes)
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  • duskpin seedling style avatar for user §+€\/€n
    How come we can’t just add it like a regular adding problem?
    (5 votes)
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  • aqualine ultimate style avatar for user Sophie M.
    I know what to do now! Thanks for the video to help me! Merry Christmas!! 🎄⛄
    (4 votes)
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    • duskpin tree style avatar for user KK
      Let's add 19 and 3/18 to 18 and 2/3. So I like to separate out the whole number parts from the fraction parts. So 19 and 3/18 is the same thing as 19 plus 3/18. And to that, we are going to add 18 and 2/3, which is the same thing as 18 plus 2/3. Now we can separately add the whole number parts. So we could add the 19 to the 18. So we could do 19 plus 18. And then we can add the fraction parts-- let me do this in green-- plus 3/18 plus 2/3. Now 19/18, pretty straightforward. That is what? Let's see. 19 plus 19 would be 38. So this is going to be 1 less than that. It's going to be 37. So that gives me 37. And then 3/18 plus 2/3, to add them, I need to have the same denominator. And the least common multiple of 18 and 3 is 18. So let's convert 2/3 to something over 18. So 2/3, if I want to write it as something over 18, well, I multiplied the denominator by 6, so I'd also have to multiply the numerator by 6. So it's the same thing as 12/18. So I can rewrite 2/3 as 12/18. And now I can add these two things together. That's going to be-- so I have 37 plus-- it's going to be something over 18-- plus something over 18. 3 plus 12 is 15, plus 15/18. And so expressing this as a mixed number, I get 37 and 15/18. And that's the right number. But we can simplify it even more. We can simplify the 15/18. Both the numerator and the denominator are divisible by 3. So let's divide them both by 3. And we're not changing the value because we're doing the same thing to the numerator and the denominator. And so this gives us, we still have our 37, but the numerator is now 5, and the denominator is now 6. So we get 37 and 5/6. And we're done.
      (2 votes)
  • blobby green style avatar for user Leeanne Hedstrom
    i do not git this video. merry Christmas!
    (4 votes)
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  • blobby green style avatar for user 701893
    I don't get it like WHAT
    (4 votes)
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    • blobby green style avatar for user hweng26
      wut dont u get its pretty straight forward foe exm. if u wanted to find lets say 1 1/2 + 2 6/8
      u would covert the mixed number into an improper fraction so the first number would be 1 1/2 u would take the 2 and times it by the whole number which is the big 1 then u would add the 1 thats above the 2 and get 3/2 for the second number u would do the same thing and should get 22/8 then u see we have unlike denominators so wut times 2 would get u to 8 it would be 4 so u muliply 3/2 x 4/4 and get 12/8 then u add! and ta dah!!UwU
      (1 vote)
  • purple pi purple style avatar for user ptutorhcms
    are there tricks to simplifying odd fractions?
    (2 votes)
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  • blobby blue style avatar for user 🍪Emma
    If I have 1 9/9 and 6 7/8 do I still have to convert it since 8/8 equals to one whole? :)
    (3 votes)
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    • piceratops ultimate style avatar for user EmmaB
      Because you're adding you have to do what you did with adding regular fractions, make the denominators of your proper fractions in the mixed fractions the same, and then you can start adding the whole numbers then the numerators of the proper fractions :) Same when subtracting mixed fractions. Then simplify at the end if you can do.
      (1 vote)
  • blobby green style avatar for user bananaboy26
    crap
    (3 votes)
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  • starky ultimate style avatar for user 𝕍𝔼𝔻𝔸
    STEPS FOR ADDING FRACTIONS
    note: adding fractions is different from normal addition for a reason!
    1.you need to find a common denominator if the denominator for both of the fractions is not the same
    Steps to find out common denominator:
    ex: 4/49+3/7 - 49 is a multiple of 7 , to get 49 you multiply 7x7
    2.now all you have to do is multiply 4x7 which gives you 28
    so then your fraction will become 28/49+3/7
    3.then you just add the numerator

    I hope this helps!
    (2 votes)
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Video transcript

Let's add 19 and 3/18 to 18 and 2/3. So I like to separate out the whole number parts from the fraction parts. So 19 and 3/18 is the same thing as 19 plus 3/18. And to that, we are going to add 18 and 2/3, which is the same thing as 18 plus 2/3. Now we can separately add the whole number parts. So we could add the 19 to the 18. So we could do 19 plus 18. And then we can add the fraction parts-- let me do this in green-- plus 3/18 plus 2/3. Now 19/18, pretty straightforward. That is what? Let's see. 19 plus 19 would be 38. So this is going to be 1 less than that. It's going to be 37. So that gives me 37. And then 3/18 plus 2/3, to add them, I need to have the same denominator. And the least common multiple of 18 and 3 is 18. So let's convert 2/3 to something over 18. So 2/3, if I want to write it as something over 18, well, I multiplied the denominator by 6, so I'd also have to multiply the numerator by 6. So it's the same thing as 12/18. So I can rewrite 2/3 as 12/18. And now I can add these two things together. That's going to be-- so I have 37 plus-- it's going to be something over 18-- plus something over 18. 3 plus 12 is 15, plus 15/18. And so expressing this as a mixed number, I get 37 and 15/18. And that's the right number. But we can simplify it even more. We can simplify the 15/18. Both the numerator and the denominator are divisible by 3. So let's divide them both by 3. And we're not changing the value because we're doing the same thing to the numerator and the denominator. And so this gives us, we still have our 37, but the numerator is now 5, and the denominator is now 6. So we get 37 and 5/6. And we're done.