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### Course: 4th grade (Eureka Math/EngageNY) > Unit 1

Lesson 1: Topic A: Place value of multi-digit whole numbers- Place value blocks
- Place value blocks
- Place value tables
- Place value tables
- Comparing with multiplication
- Comparing with multiplication and addition: giraffe
- Compare with multiplication
- Finding place value
- Identify value of a digit
- Creating the largest number
- Creating largest or smallest number
- Multiplying whole numbers by 10
- Multiply whole numbers by 10
- Dividing whole numbers by 10
- Divide whole numbers by 10
- Multiply and divide by 10
- Understanding place value
- Place value when multiplying and dividing by 10
- Place value when multiplying and dividing by 10
- Writing numbers in words and standard form
- Writing a number in expanded form
- Write whole numbers in expanded form
- Whole numbers in expanded form review
- Write numbers in written form
- Whole numbers in written form review
- Regrouping numbers into various place values
- Regrouping whole number place values
- Adding whole numbers by their place values
- Regroup whole numbers

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# Dividing whole numbers by 10

Lindsay finds a pattern from dividing whole numbers by 10.

## Want to join the conversation?

- so its like if its 80 divides by 10 its going to be a single digit from 80 so 8?(70 votes)
- Yes, move the dot to the left as many zero you have.

80=80.0

80.0 / 10 = 8.00

435.45 / 100 = 4.3545

0.23 / 10 = 0.023

etc(52 votes)

- i need help with math the ones that have a number then this =(19 votes)
- so say have 10 divided by 2 that would = 5 since 5x2=10.

Another example is if you have 100 divided by 10 that would equal 10 since 10 x 10= 100. Get it now(19 votes)

- I don’t understand 10x990,000! I’m having a meltdown!(11 votes)
- To multiply any whole number by 10, attach a 0 on the right. So 10x990,000 = 9,900,000.

Have a blessed, wonderful day!(20 votes)

- this doesn't make any sense to me can anyone explane?(14 votes)
- when you are dividing by 10 like 650 divided by 10 you simply take away the 0 at the end of the first number and thats the answer so with 650 divided by 10 the answer is 65. I hope that helped(12 votes)

- What if their was no zero in the ones place? What if their was a different number?(8 votes)
- then you just move the decimal to the right one place(3 votes)

- Is this for decimals or regular whole number?(6 votes)
- Wait, if we divide by 10 then it just takes away a 0 Right?(4 votes)
- Multiplying is adding q zero and djviding is taking a zero off. Can someone show me another way to divide and multiply? I'd like using answers from people instead of google. =](3 votes)
- Remember it from start to end again and again and again and again until it sticks in your brain FOREVER(2 votes)

- is 300,000% 10,000 3,000? I need help with it(3 votes)
- . what is 1,870 - 10 is?

. .(3 votes)- 1,870 - 10 is 1,860. 1,870 / 10 is 187, because you can eliminate the 0's on the ends of both numbers.(1 vote)

## Video transcript

- [Voiceover] Dividing by 10,
a lot like multiplying by 10, creates a pattern with numbers. So let's dig in and look at dividing by 10 and look at happens when we divide by 10 and see if we can figure out that pattern and maybe even how it relates to the pattern for multiplying by 10. Let's take a fairly simple one to start. Let's say something like 30 divided by 10. One way to think about this
is we're taking the number 30 and we're dividing it into groups of 10. So let's see how many groups
of 10 it takes to make 30. One group of 10 is 10,
so that's not enough, plus a second group is 20,
plus a third group is 30. So 30 can be thought of
as 10 plus 10 plus 10, or three groups of 10. So if we divide 30 by 10,
divide 30 into groups of 10, we end up with three groups. Let's try another one, maybe
something slightly trickier, maybe let's go with 110 divided by 10. And again, we're
dividing, we're taking 110 and dividing it into groups of 10. So let's see how many groups
of 10 it takes to get to 110. Here's one 10, plus another is 20, 30, 40, 50, another 10 gets us to 60, 70, 80, we're getting closer, 90, 100, and 110. So this right here is
how many groups of 10 it takes us to get to 110. So let's see how many groups is that. One, two, three, four, five,
six, seven, eight, nine, 10, 11, our solution is 11. If we have 110 and we
divide it into groups of 10, we end up with 11 groups. Let's look at these first two, let's pause here and
see if we see a pattern. 30 divide by 10 was three,
110 divided by 10 was 11, so what happened to the 30 in the 110 to get these quotients? And what happened is the zero, the zero on the end was taken off. Our solution is the same, but with the zero taken off the end. Here again, the solution is the same with a zero taken off the end. And if we remember for
multiplication, it was the opposite. If we had two times 10
instead of dividing, times 10, our solution was 20, or two, our original number,
with a zero added to the end. Remember, in another one,
something like 13 times 10, our product, our solution is a 13, the original number, with
a zero added to the end. So in multiplication,
when we multiply by 10, we add a zero to our
whole number at the end, and when we divide, we
do the opposite by 10, we take off a zero from the
end of our whole number. So knowing that pattern,
let's try one more, maybe one where we don't
work out all the 10s, but just try to use the
pattern to solve it. If we had somethig like, say, 7,000 divided by 10, well, our solution is going to be 7,000 but with a zero taken off of the end because we're dividing by 10, so instead of 7,000 we would have 700. 7,000 divided into groups of
10 would be 700 groups of 10, so our solution is 700. Let's take this all a step
further and let's think about what dividing by 10
is doing to these numbers, to 30, to 110, to 7,000, in
terms of their place value. So here's a place value chart. Let's use it to look at one of the numbers we already tried, something like 30. And when we divided 30 by 10, remember what happened to the three, instead of being three 10s,
our solution was three ones. The three moved one
place value to the right, and the zero really did too,
it would move after a decimal, which would be 3.0, which
is the same as three, which is the reason we didn't
need to write that zero, the reason that we could cross it off. So our number, instead of being three 10s, when we divided by 10, became three ones. Let's look at a little
bit trickier of one. We also tried 7,000, so that
would be seven thousands, zero hundreds, zero 10s, and zero ones, and when we divided by 10, our seven in our thousands
place became seven hundreds, and the zero hundreds became zero 10s, and zero 10s became zero ones. And that last zero we
were able to cross off and move to after the decimal. So 7,000 divided by 10 was 700. Again, everything moved one
place value to the right. So there's two ways to
think about dividing by 10. We could either say you
drop a zero off the end, or we could say that you move every digit one place value to the right. Let's think about it again
in terms of place value with a new number, let's
try something like 630. If we divide 630 by 10, we're
going to move everything one place value to the
right, so the six hundreds will become six 10s, three
10s will become three ones, and the zero ones will
move after the decimal. So we can say that 630 divided by 10 is equal to 63, or six 10s and three ones. So again, two ways to
think about dividing by 10. Either we can cross off a
zero, or we move every digit, each digit one place value to the right.