Main content

### Course: 4th grade > Unit 1

Lesson 4: Regrouping whole numbers# Regrouping numbers into various place values

Sal regroups 4500 different ways. Created by Sal Khan.

## Want to join the conversation?

- how did you get 500 in the equation -4000 + 500 =3000(5 votes)
- Since the number you're working with is 4500, 4 is in the thousands place, so you have 4000, and 5 is in the hundreds place, so you get 500. The other digits are zeroes, so you only consider the 4000 +500. Hope I helped!(6 votes)

- Is place value a bit like multiplying by tens and stuff or what? This video is confusing(1 vote)
- Think of 4 slots, and each slot has a value. Slot 1, farthest to the right, is 1000. Then the next is 100, so on and so on. Now, you can assign a different number to each slot. So, Slot 1 has a three assigned to it, so it's 3,000. You can do this with any 1 digit, to any slot. So

Slot 1 (thousand) = 3

Slot 2 (hundred) = 6

Slot 3 (ten) = 4

Slot 4 (one) = 0

We can look at it this way "slot number one has 3, and since 3 is thousands, we have ten thousands. And since slot 2 (hundreds) has 6, we have six hundreds" and so on and so on. So take the number in the slot, and multiply it by the slot's value. do that for all the slots, then add them together.(8 votes)

- i don't get how you can have 3 thousand and some hundreds which is equivalent to 4500. Unless if there are 15 hundreds(0 votes)
- That is exactly how you get 3 thousands and some hundreds equivalent to 4500.

I.e. 3000 + 1500 equals 4500.(3 votes)

- i do not know how to do this(31 votes)
- maybe I can help(6 votes)

- if you focus it will be faster.(17 votes)
- You can go to the Youtube settings and make it faster to!(18 votes)

- are we just adding on to 3,000 to make it equal to 4,500(17 votes)
- Yes, the question is asking how many hundreds added to 3000 will give us 4500.(10 votes)

- At0:38, why did he use 3,000? It confused me.(9 votes)
- i dont know but i know it was a ex. :)(9 votes)

- where did you get the 3000(6 votes)
- Please clarify your question. In the beginning, 3000 was part of the original question.(9 votes)

- Why can't you just start with the amount of thousands automatically?(4 votes)
- place value could be helpful in our lives right(3 votes)

## Video transcript

We have 4,5000 equals 3
thousands plus how many hundreds, question
mark hundreds? So let's write this
left-hand side, but I'm going to
write it out in terms of thousands and hundreds. So I'll write the
thousands in orange. So this is equal to
4 thousands, which is the same thing as just 4,000,
plus 500, which you could also view as 5 hundreds. So this is the left-hand side. Now let's look at
the right-hand side. We have 3 thousands. So it's 3 thousands. Now let's not even
look at this right now. Let's just think
about what do we have to add to this
right-hand side in order to get the
same thing that we have on the left-hand side? Well, if you compare
the 3,000 and the 4,000, you see you have an
extra 1,000 over here. So let's add an extra
1,000 on the right. So we're going to
add one extra 1,000. And now we just have
3,000 plus 1,000. This makes it the 4,000. But then, of course, we
also need another 500. So we're going to need
plus a 500 right over here. So in order for these
two things to be equal, we need to say 4,000 plus 500
is equal to 3,000 plus 1,500. Now, the way they've set
this up, we need to express-- so it almost looks the same. On the left-hand
side, this is 4,500. So this right over here, this
is the same thing as 4,500. This is this right over here. And on the right-hand
side, we have 3 thousands. So that's this right over here. That's the 3 thousands. And then we just need to
express this as hundreds. So 1,500, this is the
same thing as 15 hundreds. So let's rewrite everything. We can rewrite this
as saying 4,500, just to get the exact same form
that they wrote it over there. So we could write 4,500 is
equal to 3 thousands plus-- now we have to just write
this in terms of hundreds. Well, This is 15 hundreds. Literally, if you
took 15 times 100, it's going to be equal to 1,500. So this could be viewed as 15
hundreds, so plus 15 hundreds. So in this situation, the
question mark is equal to 15.