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## 5th grade

### Unit 9: Lesson 4

Divide whole numbers by decimals- Visually dividing a whole number by a decimal
- Dividing a whole number by a decimal on a number line
- Division strategies for decimal quotients
- Divide whole numbers by decimals visually
- Pattern when dividing by tenths and hundredths
- Divide whole numbers by 0.1 or 0.01
- Dividing whole numbers by decimals examples
- Divide whole numbers by decimals
- Divide decimals: FAQ

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# Dividing whole numbers by decimals examples

CCSS.Math:

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## Want to join the conversation?

- I don't understand the specific lesson.can you help me Salman Khan?(9 votes)
- 8 divided by 0.4 is basically 80 divided by 4, which is 20. So, if you do the decimal version, it is 20 still, (using a calculator) So no worries, Sal did it a bit weird. But it is 20, in simple terms I you have to do this simple equation==== 8x10/4(5 votes)

- Are there more ways to divide decimal’s(4 votes)
- Just we can change the decimal numbers to whole number and then divide.

For ex: 8 /0.4 = (8 x10)/ (0.4 x10) = 80 / 4 = 20(4 votes)

- How would you say 4,800 hundredths? I noticed Sal stumbled with the pronunciation, so i was wondering. Would you say it, four-thousand-eight-hundredths, or a different way? Let me know what you think.(3 votes)
- If you wanted to say it as a whole than you would say forty eight(2 votes)

- I don't understand(2 votes)
- That makes so much sense. Thanks for helping me Sal!(2 votes)
- why is this so hard(1 vote)
- it's much easier if you think of it as a multiplication puzzle instead of a division puzzle. don't ask me why it's taught this way.(3 votes)

- why is there so much work that u dont need(1 vote)
- I actually find it quite simpler the way Sal did it- I think it’s kind of personal to a person specifically. Like how some people can’t stand brussel sprouts, and some love it. Find an easy way that works for you, and stick with it! :)(1 vote)

- This way for me is easier... So you make the decimal (dividend) in to a whole number and then see whether if it is in the tenths hundredths or thousandths place ect. Once you have determined which place it is in multiply the whole number (divisor) 10, 100, 1000, ect. To find how much you must know the place value of the decimal if its in the tenths multiply by 10 if its in the hundredths multiply be 100 if in the thousandths multiply by 1000. Then do the long division(1 vote)
- if you give me an up vote and comment "need help" we can talk and figure it out.(0 votes)

## Video transcript

- [Instructor] Let's
say we wanna figure out what eight divided by 4/10 is. Pause this video and try to
figure it out on your own before we do it together. All right, now one way to approach this is to think about everything
in terms of tenths. And why tenths, you ask? Well, I just described
the second number as 4/10. So what would eight be in terms of tenths? Well, we know that one whole is equal to 10/10, so eight wholes is going
to be equal to 80/10. So I could write that down over here. Instead of eight, I can
write that as 80/10. And I'm taking 80/10 and
I'm dividing that by, divided by 4/10. I'm just writing out, 4/10. So if I have 80 of something, and if I'm diving it into groups
of four of that something, how many equal groups am I going to have? Well, I'm gonna have 80
divided by four groups, or 80 divided by four,
eight divided by four. Actually, let me just write that down. This is going to be equal to 80 over four or 80 divided by four. And eight divided by four is two, so 80 divided by four is
going to be equal to 20. So eight divided by 4/10 is equal to 20. Another way that you
could think about that is to rewrite eight divided by 4/10 as eight over 4/10. Over 4/10. And then if you wanted to rewrite this, you could say, "Hey, can
I multiply the numerator "and the denominator by some
quantity that'll get rid "of the decimal in the denominator?" Well, I could multiply
the denominator by 10. And if I don't wanna change
the value of the fraction, I have to multiply the
numerator by that same amount. Well, what does that get us? Well, this is going to be equal to, in the denominator right over here, I'm just going to have a four. So we got rid of the decimal. In the numerator, I am going to get 80. So once again, we get 80 over
four, which is equal to 20. Let's do another example, but in this case we'll
deal with hundredths. So let's say we want to figure out what is 48 divided by 0.24 or 24/100? Pause this video and
try to figure that out. All right, well, we can
do something very similar. This time we're dealing with hundredths, so we could try to express everything in terms of hundredths. So 48 is equal to how many hundredths? Well, we know that one
is equal to 100/100, so 48 is going to be equal to 48 times 100/100. Maybe I'll just write it like that. Or you might be able to
say, "Hey, that's 4,800 "or 4,800/100." So let's just, actually,
I'll write it that way. This is going to be 4,800/100 divided by, this is 24/100. 24/100. And so what's that going to be? Well, same logic as we used up here. If I have 4,800 of something
or 4,800 of something and if I'm dividing it into equal groups of 24 of that something, well, I'm going to have 4,800
divided by 24 equal groups. So this is going to be equal to 4,800 over 24. We could express 4,800 as, of
course, 48 times a hundred. So this is equal to 48 times 100 over 24. And of course, you could
view this as the same thing as this is equal to 48 over 24. 48 over 24, and many of you
might have already done it in your head, times 100. What's 48 divided by 24? Well, that is going to be equal to two. So two times a hundred is equal to 200. So this right over here is equal to 200. You can also do it in this type or do it similar to the way we did this where instead of
expressing it out as words, you could express it as 48 over 24/100. And instead of multiplying the numerator and denominator by 10, maybe you wanna multiply
it by something else to get whole numbers in both
the numerator and denominator. Think about that after this video, and try to work it out that way as well.