all you need to do is just multiply the whole number by the denominator

Yes, but I would like to point out that if the number has a numerator that is not one, you need to do it the way Mr. Sal shows you. :)

One thing I don't understand, when we divide 3 by 1, we get a result of 3, but when we divide 3 by 1/4 we a get a number higher than 3, I'm kind of confused, can someone explain?

When we divide 3 by 1, we are trying to find how many 1's there are in 3. In this case, there are 3 ones in 3. The same goes when we divide by fractions, when we divide 3 by 1/4, we are trying to find how many 1/4's there are in 3. There are 4 quarters in 1, so there must be 3 times as many quarters in 3 than there are in one. 4 times 3 is 12, so there are 12 1/4's in 3. Another way to think about this is to use logic. 3 divided by 1 is 3. 3 divided by 2 is 1.5. So we can see that the answer gets smaller as the divisor gets larger, therefore, the answer must get larger as the divisor gets smaller. Hope this helps!

I have found that if you do the whole number times the denominator you can usually get the correct answer, but I've only done it on simpler problems. Does this process always work?

Yes, when dividing a whole number by a unit fraction, multiplying the whole number by the unit fraction's denominator always works! This is because, for any numbers a and b with b nonzero, we have a divided by (1/b) = a times (b/1) = (a/1) times (b/1) = ab/1 = ab. Have a blessed, wonderful day!

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MAP Recommended Practice

Course: MAP Recommended Practice > Unit 34

Lesson 31: Dividing whole numbers by unit fractions

Dividing a whole number by a unit fraction

Name: Dividing a whole number by a unit fraction
Uploaded: 2017-11-21T23:07:36Z
Description: Sal uses a fraction model to divide a whole number by a fraction.

CCSS.Math:

5.NF.B.7

5.NF.B.7b

Google Classroom

Sal uses a fraction model to divide a whole number by a fraction.

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Arbaaz Ibrahim
Posted 5 years ago. Direct link to Arbaaz Ibrahim's post “One thing I don't underst...”
One thing I don't understand, when we divide 3 by 1, we get a result of 3, but when we divide 3 by 1/4 we a get a number higher than 3, I'm kind of confused, can someone explain?
Button navigates to signup pageComment on Arbaaz Ibrahim's post “One thing I don't underst...”
(6 votes)
Answer
- supermonkey21
  Posted 5 years ago. Direct link to supermonkey21's post “When we divide 3 by 1, we...”
  When we divide 3 by 1, we are trying to find how many 1's there are in 3. In this case, there are 3 ones in 3. The same goes when we divide by fractions, when we divide 3 by 1/4, we are trying to find how many 1/4's there are in 3. There are 4 quarters in 1, so there must be 3 times as many quarters in 3 than there are in one. 4 times 3 is 12, so there are 12 1/4's in 3. Another way to think about this is to use logic. 3 divided by 1 is 3. 3 divided by 2 is 1.5. So we can see that the answer gets smaller as the divisor gets larger, therefore, the answer must get larger as the divisor gets smaller. Hope this helps!
  Comment on supermonkey21's post “When we divide 3 by 1, we...”
  (41 votes)
Vaishavi Pandey
Posted 4 years ago. Direct link to Vaishavi Pandey's post “So, do you basically do t...”
So, do you basically do the whole number times the denominator of the unit fraction to get your answer?
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(22 votes)
Answer
- schulzchristi18
  Posted a year ago. Direct link to schulzchristi18's post “Why can't I vote for you?...”
  Why can't I vote for you? I don't even know why we are vote?
  Comment on schulzchristi18's post “Why can't I vote for you?...”
  (1 vote)
sbritches626
Posted 3 years ago. Direct link to sbritches626's post “all you need to do is jus...”
all you need to do is just multiply the whole number by the denominator
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(8 votes)
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- 🖤🤍JetCheetah🤍🖤
  Posted 3 years ago. Direct link to 🖤🤍JetCheetah🤍🖤's post “Yes, but I would like to ...”
  Yes, but I would like to point out that if the number has a numerator that is not one, you need to do it the way Mr. Sal shows you. :)
  Button navigates to signup page
  (2 votes)
Sir.Isaac.Newton.06
Posted 5 years ago. Direct link to Sir.Isaac.Newton.06's post “I have found that if you ...”
I have found that if you do the whole number times the denominator you can usually get the correct answer, but I've only done it on simpler problems. Does this process always work?
Button navigates to signup pageComment on Sir.Isaac.Newton.06's post “I have found that if you ...”
(4 votes)
Answer
- Ian Pulizzotto
  Posted 5 years ago. Direct link to Ian Pulizzotto's post “Yes, when dividing a whol...”
  Yes, when dividing a whole number by a unit fraction, multiplying the whole number by the unit fraction's denominator always works!
  This is because, for any numbers a and b with b nonzero, we have
  
  a divided by (1/b) = a times (b/1) = (a/1) times (b/1) = ab/1 = ab.
  
  Have a blessed, wonderful day!
  Comment on Ian Pulizzotto's post “Yes, when dividing a whol...”
  (4 votes)
dharan.krishnakumar
Posted 3 years ago. Direct link to dharan.krishnakumar's post “It is easy 3 divided 1/4 ...”
It is easy 3 divided 1/4 is just doing 4x3
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(5 votes)
Answer
kjobrien82
Posted 5 years ago. Direct link to kjobrien82's post “how would you divide a wh...”
how would you divide a whole number by a fraction when it's not 1/2, 1/3,1/4
for example 2 / 5/6. In a different module on proportions, the answer they give is a mixed numeral, but I can only get a fraction: 5/12
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vandortle68
Posted 4 months ago. Direct link to vandortle68's post “Im in seventh grade and i...”
Im in seventh grade and i cant figur it out gfkbhvjchdfjcgm
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(4 votes)
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Lachlan
Posted a year ago. Direct link to Lachlan's post “When dividing fractions l...”
When dividing fractions like 1/9 divide by 4, you only need to do 1/ 9 x 4 = 1/36
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(4 votes)
Answer
- Ian Pulizzotto
  Posted a year ago. Direct link to Ian Pulizzotto's post “This is essentially corre...”
  This is essentially correct. Revise the last equation to say 1/(9 x 4) = 1/36, to make it clear that 9 and 4 are multiplied first.
  
  Have a blessed, wonderful day!
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  (1 vote)
2028bernt25
Posted 2 years ago. Direct link to 2028bernt25's post “hello frens :3 i wish luc...”
hello frens :3 i wish luck on your assignment! :3
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(2 votes)
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theo
Posted 2 years ago. Direct link to theo's post “why do you say pizzas lik...”
why do you say pizzas like pieses
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- trayevon.williams
  Posted 4 months ago. Direct link to trayevon.williams's post “i really dont know”
  i really dont know
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Video transcript

- Lets think about what three divided by one fourth is equal to. Pause this video and see if you can figure it out on your own. And I'll give you a hint, take three wholes and divide it into pieces or sections that are each one fourth of a whole and then think about how many sections you have. Alright now lets work through this together. Now let me draw three wholes. And so lets say this is... I'm gonna hand draw it, so its not gonna be perfect. But lets say that is one whole right over there. This is two wholes right over there. And then I have my third whole just like that. And now I'm going to divide it into pieces or sections that are each one fourth of a whole. So this first whole is four pieces that are each one fourth each, of four fourths. And then I have another four fourths right over here. And then I have another four fourths right over here. Another way to think about it, I took the three wholes, and I divided it into fourths. So if you divide it into fourths how many pieces am I going to have? Well this is pretty straight forward, you have one two three four five six seven eight nine ten 11 12 pieces. And I didn't even have to count that, each whole is gonna be four fourths. So three wholes is going to be three times four fourths, or 12 pieces or 12 sections. So that is going to be equal to 12. Another way to think about it is if you take three and you divide it into equal sections that are each a fourth you are going to have 12 equal sections.