If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content

Subtracting mixed numbers with like denominators word problem

Sal solves a word problem involving mixed number subtraction by using a visual model.

Want to join the conversation?

  • spunky sam blue style avatar for user proctormc64
    On one of the word problems you have to subtract a mixed fraction a whole number. I don't see a video to explain this. Can you help please.
    (7 votes)
    Default Khan Academy avatar avatar for user
    • winston baby style avatar for user Gus super mario 64
      Also, when you multiply two fractions less than one, your answer actually gets smaller. Think about the multiplication sign as saying "groups of." 3 x 8 = 24 means 3 groups of 8 are 24.

      With fractions, you're still saying that. 1/2 of a group of 12 is 6. 1/3 of a group of 9 is 3.

      The procedure for two fractions is to multiply across -- numerator times numerator and denominator times denominator.

      1/2 x 2/3 is saying that you have half of a group that was 2/3 of a full group to begin with. So, you had 2 thirds, but not you only have half of that, or 1/3

      numerators : 1 x 2 = 2
      denominators: 2 x 3 = 6

      So the answer is 2/6, which can be reduced to the equivalent fraction 1/3.
      (4 votes)
  • male robot hal style avatar for user 🔥
    Is there any way you explain it better because I steel don't get thank you😎
    (8 votes)
    Default Khan Academy avatar avatar for user
    • winston baby style avatar for user Gus super mario 64
      Also, when you multiply two fractions less than one, your answer actually gets smaller. Think about the multiplication sign as saying "groups of." 3 x 8 = 24 means 3 groups of 8 are 24.

      With fractions, you're still saying that. 1/2 of a group of 12 is 6. 1/3 of a group of 9 is 3.

      The procedure for two fractions is to multiply across -- numerator times numerator and denominator times denominator.

      1/2 x 2/3 is saying that you have half of a group that was 2/3 of a full group to begin with. So, you had 2 thirds, but not you only have half of that, or 1/3

      numerators : 1 x 2 = 2
      denominators: 2 x 3 = 6

      So the answer is 2/6, which can be reduced to the equivalent fraction 1/3.
      (1 vote)
  • starky tree style avatar for user 71025
    anybody like pizza?
    (6 votes)
    Default Khan Academy avatar avatar for user
  • piceratops sapling style avatar for user Gaspard
    Why does Lily measure the puddles.
    (5 votes)
    Default Khan Academy avatar avatar for user
  • duskpin ultimate style avatar for user Ibrahiim
    I don`t understand this can you make it clearer
    (5 votes)
    Default Khan Academy avatar avatar for user
    • winston baby style avatar for user Gus super mario 64
      Also, when you multiply two fractions less than one, your answer actually gets smaller. Think about the multiplication sign as saying "groups of." 3 x 8 = 24 means 3 groups of 8 are 24.

      With fractions, you're still saying that. 1/2 of a group of 12 is 6. 1/3 of a group of 9 is 3.

      The procedure for two fractions is to multiply across -- numerator times numerator and denominator times denominator.

      1/2 x 2/3 is saying that you have half of a group that was 2/3 of a full group to begin with. So, you had 2 thirds, but not you only have half of that, or 1/3

      numerators : 1 x 2 = 2
      denominators: 2 x 3 = 6

      So the answer is 2/6, which can be reduced to the equivalent fraction 1/3.
      (1 vote)
  • blobby green style avatar for user lsta9265
    I don’t get , can you help me?
    (4 votes)
    Default Khan Academy avatar avatar for user
    • winston baby style avatar for user Gus super mario 64
      Also, when you multiply two fractions less than one, your answer actually gets smaller. Think about the multiplication sign as saying "groups of." 3 x 8 = 24 means 3 groups of 8 are 24.

      With fractions, you're still saying that. 1/2 of a group of 12 is 6. 1/3 of a group of 9 is 3.

      The procedure for two fractions is to multiply across -- numerator times numerator and denominator times denominator.

      1/2 x 2/3 is saying that you have half of a group that was 2/3 of a full group to begin with. So, you had 2 thirds, but not you only have half of that, or 1/3

      numerators : 1 x 2 = 2
      denominators: 2 x 3 = 6

      So the answer is 2/6, which can be reduced to the equivalent fraction 1/3.
      (1 vote)
  • starky sapling style avatar for user 👻🖤😈MESSI🫠👻🎃😇
    Boss Baby can you please stop putting the same thing thank you😁😁
    (4 votes)
    Default Khan Academy avatar avatar for user
  • piceratops ultimate style avatar for user mccaymaddox
    Me to I like pizza🍕🍕🍕🍕🍕🍕🍕🍕🍕🍕🍕
    (3 votes)
    Default Khan Academy avatar avatar for user
  • blobby green style avatar for user tr8019
    You don't need yo use the number line you can just add the numerator (っ °Д °;)っ
    (3 votes)
    Default Khan Academy avatar avatar for user
  • aqualine tree style avatar for user bluuze
    how do
    (2 votes)
    Default Khan Academy avatar avatar for user

Video transcript

- [Instructor] After a rain storm, Lily measures the depth of several puddles in her backyard. She records her results in a table. So here are three different puddles and she measures the depth in inches. We're asked how much deeper was the puddle under the swing than the puddle on the sidewalk. So pause this video and see if you can figure that out. So they say how much deeper was the puddle under the swing, so that's this one right over here it's one and 1/4 inches deep it's under the swing. How much deeper was that than the puddle on the sidewalk? Do that in a different color, the puddle on the sidewalk. And we see here the puddle on the sidewalk is 2/4 inches deep, so what we could do is subtract the 2/4 from the one and 1/4. So we could write one and 1/4 minus 2/4 could write it like that, and we could try to subtract the fraction part 2/4 from the fraction part of this mixed number up here from 1/4 but we immediately have a problem 'cause 2/4 is a larger fraction than 1/4, so how do we deal with that? Well the key is to realize that one can be rewritten as a fraction, one and 1/4 is the same thing as one plus 1/4 which is the same thing as another way to write one in terms of fourths is 4/4 so this is 4/4 plus 1/4 which is going to be equal to 5/4. So now you can do this as 5/4, this number is the same thing as 5/4 minus 2/4, let me rewrite it, minus 2/4, minus two over four. And that's pretty straightforward if I have five of something and I subtract two of it, I'm going to have three of that something in this case I'm talking about 3/4. So this is going to be 3/4 so how much deeper was the puddle under the swing than the puddle on the sidewalk? Well 3/4 of an inch. And just another way that you could have visualized this is look I'm going to subtract 2/4 from one and 1/4. At first we could've thought of one and 1/4 as a whole like this and then it's all let me shade it, the whole and that's one and then I would have a fourth of a whole so let me divide this into four sections, so this is one and 1/4. And at first we say well how do we take away 2/4 from just that I only have 1/4 right over here and our key realization is well look, I actually this whole right over here is actually 4/4 I can think of it as 4/4, so I can think of it like this and now I have 5/4, one, two, three, four, five fourths and now I can take away two of the fourths, so I can take away one of the fourths and two of the fourths and what am I left with? Well then I am going to be left with these 3/4 right over there.