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  • - [Instructor] We're told that Katie made a table

  • to show how much time she spent on homework last week,

  • and so we can see the different subjects

  • and then how much she spent in terms of hours.

  • So in math, she spent 3/4 of an hour,

  • reading, 7/8 of an hour,

  • writing, 3/6 of an hour,

  • and then science, 5/10 of an hour.

  • And then they ask us on which activities

  • did Katie spend more than 2/3 of an hour?

  • So pause this video and see if you can figure that out.

  • All right, so we essentially have to figure out

  • which of these fractions are greater than 2/3 of an hour?

  • Which are greater than 2/3?

  • And this is all in terms of hours.

  • So first let's just think about representing 2/3,

  • so let me do it like this,

  • and I'm going to hand draw it

  • so it's not going to be perfect.

  • But if this is a whole right over here,

  • I could split it into three equal sections,

  • so I'm gonna try to do that.

  • Let me see, does that look about right?

  • So three equal sections,

  • so that would be 1/3 that would be 1/3,

  • and then that would be 1/3,

  • and then 2/3 would be two of them,

  • so I'll pick these first two.

  • Well, it doesn't have to be those first two,

  • so that's 1/3 and then 2/3.

  • So let's see if we can draw a similar visual

  • for each of these.

  • So what about 3/4?

  • So once again,

  • let's make this a whole.

  • And now if I want to think in terms of fourths,

  • I have to divide it into four equal sections,

  • so let's see.

  • If I divide it, that will be two equal sections,

  • and then I can divide each of those

  • into two equal sections, so let's see.

  • Maybe something like this,

  • and then like this.

  • So it's hand drawn, but these are four equal sections,

  • and so this would be a fourth,

  • that would be a fourth, and that would be a fourth,

  • and that would be a fourth.

  • 4/4 make a whole,

  • so three of those fourths would be one,

  • two, and then three.

  • And so you can see, and I've drawn it pretty close.

  • It's not perfect 'cause it's hand drawn,

  • but you can see that 3/4 is more of a whole than 2/3.

  • It's greater than 2/3.

  • So Katie spent more than 2/3 of an hour on math

  • because 3/4 is greater than 2/3,

  • so I like this one right over there.

  • I'll just put a square or circle around the ones

  • that she spent that extra time on

  • or the more, the greater than 2/3 of an hour on.

  • And I'll think about reading, 7/8.

  • So to compare that, I will, once again,

  • make a whole here,

  • and then I want to think about 7/8,

  • so I'm gonna split into eight equal sections.

  • So let's see, that will split into two equal sections,

  • and then, then I can go to four equal sections,

  • and then if I split each of those into two,

  • this would be eight equal sections,

  • so it may look something like this.

  • Not perfect, but I think it will get the job done.

  • So each of these are 1/8,

  • so 7/8 are going to be one, two, three,

  • four, five, six, and 7/8.

  • Clearly, once again,

  • greater than our 2/3 that we have in purple.

  • So she spent more than 2/3 of an hour on reading.

  • Now what about writing?

  • 3/6, what would that look like?

  • Well, I'll do another one right over here.

  • So if that is a whole,

  • well, actually let me split it to thirds first,

  • since we already have a bit of a reference there.

  • We can look up there and we can see.

  • Those are thirds and if we split each of those into two,

  • we're going to have sixths,

  • 'cause we'll have six equal sections.

  • So it would look something like that,

  • and then three of those six,

  • well, that's one, two, and three.

  • So we can see that 3/6 is less than 2/3

  • so I'm not gonna circle that one.

  • She didn't spend more than 2/3 of an hour on writing,

  • and then last, but not least, science.

  • 5/10.

  • Well once again,

  • we could make a whole here,

  • and let's see.

  • I want to do into 10 equal sections,

  • so that's two equal sections,

  • and each of these, I can do into five equal sections.

  • Let's see.

  • One, two, three,

  • four, five, I can do a little bit neater than that,

  • three, four and five,

  • and then one,

  • two, three,

  • four and five.

  • I can make it a little bit neater,

  • but I think this will get us

  • to where we need to get to.

  • So these are each 1/10.

  • I could write 1/10, 1/10,

  • I could do that for all 10 of these,

  • but we care about five of these tenths,

  • so one, two,

  • three, four, five of those tenths.

  • And notice, 5/10 is the exact same thing as 3/6,

  • and like 3/6, it is less than 2/3.

  • So which activities did Katie spend more than 2/3

  • of an hour on?

  • Clearly, math and reading.

- [Instructor] We're told that Katie made a table

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比較分數的文字問題 (Comparing fractions word problems)

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    林宜悉 發佈於 2021 年 01 月 14 日
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