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## 5th grade

### Unit 1: Lesson 6

Comparing decimals- Comparing decimals: 9.97 and 9.798
- Comparing decimals: 156.378 and 156.348
- Compare decimals through thousandths
- Ordering decimals
- Ordering decimals through thousandths
- Order decimals
- Comparing decimals in different representations
- Compare decimals in different forms
- Comparing decimals word problems
- Compare decimals word problems

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# Comparing decimals in different representations

Sal compares decimals numbers in standard, written, and expanded form.

## Want to join the conversation?

- At like the 2-minute mark what do you mean by re-expressing(8 votes)
- Because we're saying it again, expressing it again, which is re expressing.(3 votes)

- why does sal say "re expressing"? @2:01(6 votes)
- Re as a prefix means again which means his expressing it again.(2 votes)

- Wait I don't get the part where in the last digit if we add a zero how does it not change the value of the particular number while comparing?(4 votes)
- 2 is the same as 2.0. The decimal makes it the same.

2 = 2.0 = 2.00 = 2.000(5 votes)

- upvote me for a cookie :)(4 votes)
- what does the re-expressing mean?(1 vote)
- re-expressing the data another way by applying a function, such as a square root, log, or reciprocal. You already use some of them, even though you may not know it. We often look to re-express our data if doing so makes them more suitable for our methods.(6 votes)

- what is 420.69 in fractions form?(3 votes)
- im failing this quiz was it hard for you?(3 votes)
- manchester united or real Sociedad ? comment below.(2 votes)
- None. I support Tottenham Hotspur F.C. But if you really want me to choose, it has to be Manchester United(1 vote)

- Why are poeople weird(2 votes)
- Can't we solve this another way?(2 votes)

## Video transcript

- [Instructor] So what we're
going to do in this video is build our muscles at comparing numbers that are represented in different ways. So, for example, over here
on the left we have 0.37, you could also view this
as thirty-seven hundredths, and on the right we have 307 thousandths. And so, what I want you
to do is pause this video, and figure out, are these
equal to each other? Or is one of the larger than the other? And if one of them is,
which one is larger, and which one is smaller? Pause this video and
try to figure that out. All right, now let's try to do this together, and the way that my brain works is, I try to put them into
a common representation. So, one way we could do it is we could try to re-write this
one on the right as a decimal. So let's do that. So, we could re-write this as, it's expressing a certain
number of thousandths, so let me just make some
blanks for our various placeS. So let's say that's the one's place, and that's our decimal, that's going to be our tenth's place, that's going to be our hundredth's place, and that's going to be
our thousandth's place. So, one way to view 307 thousandths is that we have 307 of this
place, right over there. So, we could just write the seven there, the zero there, and the three over there. This over here would be 307 thousandths, and so we would have no ones. And so when you look at it this way, it's a little bit easier to compare. You can say, "all right, we have the same number of ones, we have the same number of tenths, let me compare the like
one to the like ones." So, our tenths are equal, but what happens when we
get to the hundredths? Here, we have seven hundredths, and here we have zero hundredths. So, this number on the
left is going to be larger. So, 37 hundredths is greater
than 307 thousandths. Another that we could have done this is we could have
re-expressed this left number in terms of thousandths. We could've re-written it
as, instead of 37 hundredths, we could've just said
zero point three seven, and just put another zero on the right, and this is 370 thousandths. I'll write it out. 370 thousandths. And when you look at it this way, once again it's clear
that 370 of something is more than 307 of that something. So, this quantity on the left is larger. Let's do another example, but I'll use different formats. So, let's say on the left, I'll use decimal format, I'll have zero point six, or six tenths, and then on the right, I'm going to have six
times one over a hundred. Pause this video and tell me, which of these quantities,
if either, are greater, or are they equal to each other? All right, so once again,
in order to tackle this, you really just have to think about what are different way to represent them? And really just get to
a common representation. And so, I could re-write six
tenths and six times one tenth. Six times one tenth. And this might be enough to
be able to compare the two, because six times one tenth, is that going to be
greater than, or less than, or equal to six times a hundredth? Well, a tenth is ten times
larger than a hundredth, so because this is ten
times larger than that, if you multiply is by six, well, this is going to be a larger quantity. So we could go and say, "Hey,
this is greater than that." Another way that you
might have realized that is if you were to express
this right quantity as a decimal like this. So, this is six times a
hundredth, or six hundredths. So, we could write that's our ones, that's our tenths, and then in our hundredths
place, you would have six. And if it isn't obvious
that this is less than that, you could add a zero here, and this, we would read as 60 hundredths, and 60 hundredths is for sure
larger than six hundredths. So, these are all very reasonable ways of re-representing these
numbers and putting them in the same format so we
can make the comparison and realize the one on the left,
actually in both scenarios, is larger than the one on the right.