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## Equivalent fractions

Current time:0:00Total duration:5:36

# Equivalent fractions with models

CCSS Math: 4.NF.A.1

## Video transcript

- [Instructor] So what we're
going to do in this video is think about equivalent fractions. So let's say we have the fraction 3/4, and I wanna think about what is an equivalent number of eighths? So 3/4 is equal to how many eighths? And to represent that how many, I could put a question mark there, but instead of a question
mark, I'll just put a letter. So what should y be? 3/4 is equal to y/8. What does y need to be to make this true? And before I tell you
go go pause this video and try to work on it on your own, which I will do in a little bit, I'll give you a little bit of a hint. So let's try to represent 3/4,
or I'll represent it for you. So I will do it with this rectangle. So I'm going to divide it
into four equal sections. So let's see, that would be
dividing it roughly in half. I'm hand-drawing it, so it's not perfect, but these should be equal sections. The areas of each of these
sections should be equal. So there you go, this is my
hand-drawn version of that. And so three of those four,
and I will do that in purple. Three of those four, it could be one, two, and then just for kicks
I will do this one out here. So that is 3/4 right over there. So if I were to think about
this in terms of eighths. So I'm going to draw another whole. But this time instead of just
splitting them into fourths, I'm going to split it into eighths. So let's do the fourths first, just 'cause it's easy to
look at the one above that. So that's my fourths. And then I'll divide each
of the fourths into two. So that gives me eighths. All right, almost there. The drawing is really
the hardest part here. And so each of these is an eighth. It's hand-drawn. But imagine if there were
eight equal sections. So how many eighths is equal to 3/4? Pause the video and try to
work it out on your own. All right, well, we can
just look at this visually. So this first fourth, we
could say that's equivalent to filling out this
eighth and this eighth. So that first fourth is equal to 2/8. This second fourth is equal to another two of these eighths. And then this third fourth is equal to another two of the eighths. So how many eighths have I shaded in? Well, I have one, two,
three, four, five, 6/8. So I have six over eight. So 3/4 is equivalent to 6/8. So in this scenario, y is equal to 6/8, or we could say 6/8 is equal to y. Now let's do another example. So what we could see
here in this top circle is we've divided it
into six equal sections. So each of these are one of
the six equal sections or 1/6. And we can see that one, two, three, four of them are shaded in. So what we have represented
in that top circle, that is four out of six. So what I wanna think about is how many thirds are equivalent to 4/6? Pause this video and think about it. So once again, how many
thirds are equivalent to 4/6? Instead of just putting
a question mark there, I'll put the letter x. So what should x be for these
two things to be equivalent? Or another way to think about it is four over six is equal to x over three. 4/6 is equal to how many thirds? All right, now let's do this together. And so one way you could think about it, let's see, for 1/3, for us to make this equal to 1/3, it looks like that is equivalent to what I am circling in the orange up here. And that also makes sense. If I were to divided 1/3 into two, so now I would have this would
be 1/6 and that would be 1/6. So you need 2/6 to make up 1/3, or each 1/3 is equivalent to 2/6. So this is 1/3 right over here. And that is equivalent
to two of these sixths. But we are not completely done yet. We have another two sixths. So we could say those
two sixths are equivalent to another third. And it's a little tricky
because they didn't put this sixth next to that sixth, but you could imagine if we were to move. Let's say we were to move this sixth. So I'm gonna color this one in white. So if I were to move that
sixth to right over here. So we're shading this one in instead. So then you can see that these
two sixths right over here, these two sixths are equivalent to this third right over there. So what you can see is, is that our 4/6, and remember, I moved this one over, so I'm not shading this one in anymore. But you can see the 4/6 that I've shaded in is equivalent to 2/3. Or another way to say it
is x would be equal to two. X would be equal to two. 4/6 is equal to x/3,
or 4/6 is equal to 2/3.