Decomposing whole numbers | Foundations of numbers | 3rd grade math (TX TEKS) | Khan Academy

- [Narrator] We are
asked which answer choice

describes the number,

and I'm not gonna say it
'cause that might be a hint.

This number right over here.

So pause this video and have a go at that

before we do this together.

Okay, now let's do this together.

There's a couple of ways we could do it.

We could try to express
this number in words,

or we could look at these words here

and express them as a number
and see which one matches up.

Well, I'm gonna go with the second way

because they're saying things

in not always the most standard way.

I have 14 100s here.

And you normally wouldn't say,

well, sometimes you might say it that way,

but let's just try to break it out here.

So if I have 14 1,000s
as this choice A says,

that would be 14 and then 1,000s,

and then two, that I'm adding seven 10s.

So seven 10s is what?

Well, it's seven in the
10s place and zero ones.

Or another way to think about it, it's 70.

So if I took 14,000 plus
70, what is it going to be?

And I could do this here

if I wanna line up the
place values, 14,070.

Well, I have no ones, I have
seven 10s, I have no 100s.

I have four 1000s and I have one 10,000.

I have 14,070, which is exactly the number

that they have over here.

So we luckily stumbled on,
or we looked at choice A

and it was actually the choice

that describes this number.

But let's look at the other ones

and see why that doesn't make sense.

The second choice here
still has the 14,000s.

So it still has this part right over here,

but they say seven ones.

So if you were to add 14,000

and then have seven
ones, you'd get 14,000.

And then you would add

those seven ones in the ones place.

So you would get that.

And then the last one, the sum of 14 100s

and seven 10s.

Well, they have the seven 10s part,

which we already said
is the same thing as 70.

But what does 1,400 look like?

Well, 1,400.

Let me do this in a new
color, maybe purple, 1,400.

That is one way to think about
it is you could go to the,

let's look at our place value here.

If this is ones, this
is 10s, this is 100s.

You could say you have 14 of these 100s.

Or another way to think about it

is you have four 100s and a 1,000.

Or another way of saying a 1,000 is 1,000.

That's the 1000's place.

So 1400 looks like this.

So if you were to add 1,400 and 70,

you would get 1,470,

not what they originally asked us about.

So we can feel very good about choice A.