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### Course: 3rd grade > Unit 6

Lesson 2: Comparing fractions of different wholes# Comparing fractions of different wholes

Sal compares fractions of different wholes.

## Want to join the conversation?

- Who likes icecream more than math?(19 votes)
- Me who wouldn't?!(8 votes)

- i like icecream better tan math(8 votes)
- we all love icecream more than math(6 votes)

- I do not get it(5 votes)
- then just get it(4 votes)

- Isn't one pound of gold heavier of one pound of cotton. Even though it is one pound, but it is actually different because gold would still be heavier.(4 votes)
- A pound is a unit of weight, and one pound equals one pound. So the weights are the same. Gold is heavier
**per unit of volume**(more dense) than cotton, so it takes a greater volume of cotton than gold to make a pound.

Have a blessed, wonderful day!(3 votes)

- i like ice cweam(4 votes)
- same! I also like it too(2 votes)

- is this a real question on Khan Academy? if so, why are there no pictures of store a's pizza or store b's pizza? please let me know!(4 votes)
- Sal draws the pizzas when he explains the word problem. There are no pictures provided because the whole point of the lesson is that there isn't enough information to compare the two fractions. Hope this helps!(1 vote)

- that helped a lot(4 votes)
- cool i did not ask and i don't care london i relly don't care(4 votes)
- idk

I just don't know(3 votes) - but in the previos video you said that you could not compare with different wholes(2 votes)
- There's a special case where you can. If you notice in the video, all the problems the fraction is the same. In that case, you can compare if you know their sizes.

Like compare 1/3 of a mouse to 1/3 of an elephant. It doesn't matter if you have 3/3 of a mouse, it's still going to be smaller than an elephant.(3 votes)

## Video transcript

- Amir ate 2/3 of a piece of red licorice. So, let's draw a piece
of red licorice over here and let's draw it into thirds,
so, or split it into thirds. Three equal sections, as
best as I can draw that, and he ate 2/3 of it, so
that's 1/3 right over here and then, this is a second third, So, that's 2/3, what I shaded in. This is how much of that red
licorice he would have eaten. Then, they tell us Nikko
ate 2/3 of a longer, but equally thick, piece of red licorice. So, it's gonna be equally
thick, but it's longer. So, I'm just gonna draw
something that is longer. So, that's longer, but equally
thick and he also ate 2/3 of this, but this is a longer
piece and it's equally thick, so it's actually gonna
be just a larger piece. It's gonna have more licorice in it. So, 2/3 of that, let me see if
I can split this into thirds and this is 1/3, this is a second third. Well, 2/3 of a larger piece
is going to be more than 2/3 of a smaller piece. This right over here,
this amount that he ate, it has the same width, but it's longer than this right over here. So, Nikko, because this is a
longer, but equally thick piece of red licorice, Nikko
ate more red licorice. Nikko for sure. Let's do another one. My unicorn, that's
interesting to have a unicorn. My unicorn, ate 2/6 of a
pizza from Store A, alright. I ate 2/6 of a different
pizza from Store B. Who ate more pizza? Well, it would depends. You know Store A's pizza
might look like this. Store B's pizza might look like this. So, if this was the case,
so if this is Store A and this is Store B, you eat
2/6 of this, let me divide this into sixths, so that's
halves, and that would be, and then sixths. Woops, I don't wanna do
eighths, I wanna do sixths. So, I wanna do something,
so ah that's close enough. You get the idea. So 2/6 would be like this,
one sixth, two sixths and 2/6 of this would
be, would be like this. Let me do my best shot at drawing this. I'm trying to do six equal
pieces, it's hard to hand draw, but this gets us close. 2/6 here would be that and that and if so, Store B's pizza is
bigger than Store A's pizza, then I would have eaten
more pizza than my unicorn. But, it might have been
the other way around. Maybe Store B's pizza's like this and Store A's pizza's like
this and if this was the case, my unicorn ate this 2/6
and the unicorn ate more. Or, maybe the pizzas were both this size, in which case, we would've
eaten the same amount. So, just based on what
they told us, we don't know how Store B's pizza
compares to Store A's pizza. We don't know, We don't know whether I or my unicorn got more, got more pizza. Let's do one more of these, these are fun. It took Hiro 1/3 of an hour to
run from his house to school. It took Fred 1/3 of an hour to
run from his house to school. Who took more time running to school? Now, this is a good
one, this is a good one, 'cause at first you
might say, OK, ya know, Hiro might live here, that's Hiro's house. I'll put H for Hiro here. Maybe this is the school,
I'll just try to draw larger, a larger building right
here, this is the school. And, you might say, OK
well maybe Fred's house, who knows where Fred's house is. Fred's house could be here. It could be there, it could
be over here some place. It could be over here some place. We don't know where Fred's
house is, we don't know if it's closer or further
away than Hiro's house. So, you might be saying oh, we don't know. Well, remember, they're not
saying who's house is closer or further away, or even who ran faster. They're telling us who took
more time running to school and they directly tell us
the amount of time they took. Hiro took 1/3 of an hour to run to school, from his house to school and Fred took exactly 1/3 of an hour. I don't know who ran faster or slower, or who went further distance
or shorter distance, but I know that they both
took the same amount of time. They both took 1/3 of an
hour, so this is the same. They both took the same, same time. This questions a little bit
like the famous brain teaser that some people might ask you, what weighs more, a pound of gold or a or, what would you rather
have, or actually no. What would, I know which
one you'd rather have. Which one weighs more, a pound
of gold or a pound of cotton? And people are like oh,
gold is heavier than cotton, maybe gold would make, but
we're saying a pound of gold versus a pound of cotton. Well they're both a pound,
they would weigh the same. That's kind of what we're
doing in this question right over here.