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## Arithmetic

### Course: Arithmetic>Unit 15

Lesson 3: Dividing whole numbers by unit fractions

# Dividing a whole number by a unit fraction

In this video, we'll learn how to divide a whole number by a fraction. We'll watch as three whole units are divided into sections, each being one-fourth of a whole. Then see practice problems counting these sections to understand the result of the division.

## Want to join the conversation?

• 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!
• So, do you basically do the whole number times the denominator of the unit fraction to get your answer?
• Why can't I vote for you? I don't even know why we are vote?
• 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. :)
(1 vote)
• It is easy 3 divided 1/4 is just doing 4x3
• 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
• 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!
• Im in seventh grade and i cant figur it out gfkbhvjchdfjcgm
• you are a fat boi
(1 vote)
• when my teacher did the box way i noticed that you can just multiply the whole numbers and the denomanator