## Subtitles section Play video

• - [Instructor] So they are telling us that

• r fifths is equal to eight tenths

• and we need to figure out what is r going to be equal to

• and they help us out with this number line

• where they've put eight tenths on the number line.

• That makes sense because to go from zero to one,

• they've split it into one, two, three, four,

• five, six, seven, eight, nine, ten equal jumps

• and at this point, we have gone eight of those ten

• equal jumps between zero and one so that is eight tenths

• and they've also labeled one fifth for us

• and one way to think about it is

• if we look at these bold lines,

• zero,

• one,

• two,

• three,

• four,

• five,

• if you just look at the purple, we have five equal jumps.

• So each of those jumps are a fifth

• and so it makes sense that our first jump

• right over here gets us to one fifth

• and you can see that

• that is equivalent to two of the tenths.

• I'll just write that up here so we can see that equivalence.

• One fifth is equal to two tenths

• but how many fifths is equal to eight tenths?

• Pause this video and try to figure it out.

• All right, well this is one fifth.

• If we do one more jump of a fifth, that would be two fifths.

• Then if we go another fifth,

• that will get us to three fifths

• and then if we go another fifth,

• that will get us to four fifths

• which we see is exactly equivalent to eight tenths

• and that makes sense because we also saw that

• every fifth is equivalent to two tenths.

• So four fifths is going to be equivalent

• to eight of those tenths.

• We see that very clearly right over here

• and so r is equal to four.

• Four fifths is equal to eight tenths.

• So r is equal to four.

• Let's do another example.

• What fraction is equivalent to point A?

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

• All right, so let's figure out where point A is.

• So to go from zero to one,

• we have one, two, three, four, five, six equal jumps.

• So each of these jumps are a sixth.

• So going from zero, one jump will get us to one sixth,

• then two sixths, then three sixths,

• then four sixths, then five sixths

• and so can we see four sixths in the choices?

• No I do not see four sixths.

• So we have to find an equivalent fraction to four sixths.

• So we could go choice by choice.

• The first choice has five sixths.

• Well we very clearly see that five sixths

• would be here on the number line

• which is clearly a different place than four sixths.

• So we could rule out this first choice

• but what about these other ones?

• Let's see, let's see how we can think about.

• Four fifths versus four sixths.

• Could those be equivalent?

• If I have four out of five versus four out of six,

• that's not feeling too good

• so I'm gonna put like a curly line through it.

• That's not feeling right, that if I could have

• four out of five equal jumps or five equal sections,

• that that would be the same

• as four out of six equal sections.

• If I divided it into six equal sections,

• each of those sections are going to be a little bit

• smaller than if I divided into five equal sections.

• So if I have four of each,

• they're going to be a different value.

• Actually when I talk it out like that,

• I feel even more confident that I could rule this one out.

• Now what about six fourths?

• Well one way to think about it

• is four fourths would be equal to one.

• So six fourths is going to be beyond one.

• So it's definitely not going to be where A is,

• so I could rule that one out

• and we could say oh, well maybe it's just going to be D

• but let's make sure that this makes sense.

• Two thirds, what does two thirds look like?

• Well let me try to divide this part of the number line

• from zero to one into thirds, into three equal sections.

• So I have zero there

• and then that could be one third,

• two thirds and then three thirds.

• That looks like three equal sections.

• So this is one third,

• this is two thirds, I'm making another jump of a third

• and then when I get to one, of course that is three thirds

• or we could have said six sixths

• and so point A,

• which is right over here I'm writing over it,

• that is indeed equal to two thirds.

• You can see each jump of a third is equal to two sixths.

• So it makes sense that four sixths is equal to two thirds

• or that two thirds is equal to four sixths

• so I like this one.

- [Instructor] So they are telling us that

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A1 equal equivalent number line jump choice sense

# Equivalent fractions on number lines

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林宜悉 posted on 2020/03/31
Video vocabulary