Regrouping whole number place values | Math | 4th grade | Khan Academy

- [Voiceover] Five thousands
equals how many hundreds?

There's probably a few
ways we could take this on,

but maybe let's start

by thinking about these five thousands.

Five thousands is 1,000, five times.

So let's think about
each of those thousands,

each of those five thousands.

In 1,000, how many hundreds are in 1,000?

1,000 equals how many hundreds?

Well let's see, let's count by hundreds

until we get to 1,000,

and I'll keep a little tally mark

so we can keep count of how
many hundreds it takes us

to get to 1,000.

100, 200, 300, 400, 500,

600, 700, 800, 900, 1,000.

So it took 10 hundreds, to get to 1,000.

So 1,000 is 10 hundreds.

So what would 5,000 be?

5,000 is five times as many thousands.

So we're also gonna have
five times as many hundreds.

So five thousands

will equal five times 10 hundreds,

because we have 5,000 this time,

so we have five times 10 hundreds,

or five times 10.

Five times 10 is 50.

So 5,000 equals 50 hundreds.

Another way we could think
about this is place value,

so let's do that.

Let's look at a place value chart.

Here we have a place value chart

and if we fill in five under thousands

we can see that we have
three empty spaces.

We have no hundreds, no tens and no ones,

So we need to fill those in with zeros,

or 5,000.

Again, it's 5,000.

Writing the word thousands
essentially replaced

those three zeros.

Five thousands is the same as five

with three zeros behind it,

and now we want to change
these five thousands

to be hundreds.

Well when we read this place value chart,

when we read five, when we stopped here,

five is the last number we read

and then we read the place
value above it, thousands.

So for hundreds we'll do the same thing

up until the hundreds.

We'll read the place value chart

until the place value we want

and then the place value.

So five thousands is
the same as 50 hundreds.

Five thousands is equal to 50 hundreds,

and we don't have to include
these last zeros on the end

because just like thousands
implied three zeros,

hundreds, by saying hundreds

we've essentially implied
that these zeros are there.

So five thousands is equal to 50 hundreds.

We weren't asked about tens

but we could look here
and figure it out, I bet.

Tens I would say, is 500 10s.

We'd read up through the
tens and then the tens place

because 10s have one zero after them.

That zero is implied when you say 10,

and then finally, if we
went all the way to the end,

we could also say that this
number is equal to 5,000 ones.

So any of those, five thousands,

50 hundreds, 500 tens or
5,000 ones, are equivalent.

They're all equal to each other,

but the one we were
asked about was hundreds.

So five thousands equal 50 hundreds.

Here's another one.

30 tens equals how many hundreds?

So this time we're looking
at tens and hundreds.

So let's think about how
tens and hundreds relate.

How many tens

are in 100?

How many tens are in 100 and
we could write one hundred,

the word or the number in 100.

Well to figure that out
if we don't know already,

we can count tens.

We can count by 10s and see
how many 10s it takes us

to get to a hundred.

One ten is 10, 20, 30, 40, 50

60, 70, 80, 90, 100.

So we got to a hundred
and it took us 10 tens.

There are 10 tens in 100.

So if there's 10 tens in 100

how many hundreds are in 30 tens?

Well to get from 10 tens to 30 tens,

that's three times as many tens,

so we'll also have three
times as many hundreds,

or three hundreds.

30 tens is three sets of 10 tens.

10 tens are a hundred.

So another way to think of that is 30 tens

is three sets of hundreds,
or three hundreds.

We could also think about
this in terms of place value.

Here we have this tens

and we know that tens can
be represented by a zero.

So instead of 30 10s, we
could simply write a 30

with a zero on the end,
that zero for tens,

and then over here, equal
to, we have hundreds

and hundreds can be
represented by two zeros.

So to make these equivalent,

what number will need
to fill in this spot?

And the answer again, is a three
like we already saw up top.

So 30 10s is equal to three hundreds.