Sal uses fractions to represent real-world contexts.
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- wasn't he supposed to multiply?(3 votes)
- There is no point in fractions that you need to multiply unless you are multiplying the fractions themselves. If he is saying "3 of the 4" that means 3/4. He is just putting the rest of the unit into scenarios that you can understand. If you were referring to dividing, then you only divide with fractions when you are dividing a fraction by another fraction or the top by the bottom to get a decimal. Hope this helped!(10 votes)
- I don't think this in the video but what if the numerator is bigger than the denominator?(0 votes)
- Is this like regular fractions(3 votes)
- i am so confused(4 votes)
- Can you multiply fractions?(2 votes)
- How do I post anything as a student?(2 votes)
- [Instructor] In this video we're going to think about how fractions can be used to represent things in the real world. So here we're told that on the Sharks dive team there are three divers in third grade. There are eight total divers on the team. What fraction of Sharks dive team is in third grade? So pause this video and see if you can figure that out. All right, so first of all they tell us there are eight total divers on the team. So maybe I'll represent each diver with a little circle like this, I'll try to make it look kind of like a diver, so that's not quite a circle but you get the idea, it looks like something kind of diving down. So one, two, three, four, five, six, seven, and eight. Now if we were to talk about just one diver here, just like that, that would be one out of the eight. Or we would often call that one eighth, so eight with a h at the end. That is one eighth right over there, or I could represent it like this, I could say this is an eighth, an eighth, or I could say that this is equal to 1/8. This is one of the eight members of our dive team. Now they tell us that there are three divers in third grade, what fraction of Sharks dive team is in third grade? So that is, let's say it these three, so there's three out of the eight. So if you wanted to represent that as a fraction you could represent it as 3/8 like this, or you could represent it as, if you wanted to write it out as a word, three, instead of having it three over eight, you could write three eighths like that. If you were doing this on Khan Academy there'd be some choices out there where you'd pick one of the correct choice, but you could represent the fraction of Sharks dive team that is in third grade either as three over eight, 3/8, or three and then spell out the word eighths. Let's do another example. Here we are told Yuma divided his clay into four equal parts. He made clay animals out of three of the parts. What fraction of the clay did Yuma use to make clay animals? So one again, pause this video, and think about it. All right, so let's just imagine that this is his clay, initially, and he divides it into four equal parts. And so let's say he divides it like this. And let's say that I've divided it into four equal parts, that these all have the exact amount of clay in it, it's hand drawn so it's not going to be perfect the way I drew it but let's assume they all have the exact same amount of clay. Now it says that he made clay animals out of three of the parts. So maybe, this part right over here, he was able to make a clay animal out of, this part right over here, he made a clay animal out of, and then that part, right over there, he made a clay animal out of. So what fraction of the clay did he use to make clay animals? So what would you call each of the equal parts? So if I were to just focus on that right over there, you would call that a fourth, a fourth. You could also represent it as one fourth, like that, or you could represent it as 1/4. That's if you were to just circle one of these equal parts, that one, or that one, or that one, or that one. Now if you're talking about all of his clay, what are you talking about? Well you could view it as four fourths, four fourths, or four over four, this would also be read four fourths. That would be referring to all one, two, three, four of his clay. Now if you wanted to say what fraction of the clay did Yuma use to make clay animals, we can see that three of the fourths, were used to make clay animals. So to answer that question, we would say three of the fourths, so three fourths were used to make clay animals. You can also express that as a fraction. You could also write that as 3/4 like this. You would read these the same, three fourths, or three fourths. Three out of the four equal sections of clay were used to make the clay animals.