you can remember comparing fractions by cross multiplying like this 3/5 ----- 5/3 5x5=25 and 3x3=9 so you know that 5/3 is bigger !

Another way is to notice that the numerator is greater than the denominator in 5/3 but not in 3/5!

Can you compare mixed numbers with unlike denominators?

Yes you can! Those problems will probably come in 4th and 5th grade. For example, 1/2 + 2 3/4 is a real problem. It equals 3 1/4.

How do you fill in the squares to make a fraction.

you can use the scratch pad or you can count and fill them in in your head.

Main content

4th grade (2018 edition)

Course: 4th grade (2018 edition) > Unit 3

Lesson 4: Comparing fractions with unlike denominators

Comparing fractions review

Google Classroom

Review comparing fractions with common denominators, and try some practice problems.

Comparing fractions

We can compare fractions by seeing which one takes up a greater portion of the same whole.

In this article, we will use common denominators to compare.

Want to learn about comparing fractions visually? Check out this article.

Comparing fractions using common denominators

Let's look at an example.

Compare.

start fraction, 3, divided by, 4, end fraction __ start fraction, 5, divided by, 10, end fraction

Let's change the fractions to have a common denominator of 20: (Want to review common denominators? Check out this article.)

$\begin{array}{rcl} \frac{3}{4} \times \frac{5}{5} & = & \frac{15}{20} \\ \frac{5}{10} \times \frac{2}{2} & = & \frac{10}{20} \end{array}$ ‍

Now that our fractions have the same denominator, we compare their numerators:

start color #11accd, 15, end color #11accd, is greater than, start color #1fab54, 10, end color #1fab54

start color #11accd, start fraction, 15, divided by, 20, end fraction, end color #11accd, is greater than, start color #1fab54, start fraction, 10, divided by, 20, end fraction, end color #1fab54

start color #11accd, start fraction, 3, divided by, 4, end fraction, end color #11accd, is greater than, start color #1fab54, start fraction, 5, divided by, 10, end fraction, end color #1fab54

Want to learn more about comparing fractions? Check out this video.

Practice

Problem 1

Current

Compare.

start fraction, 1, divided by, 3, end fraction __ start fraction, 6, divided by, 8, end fraction

Want to try more problems like this? Check out this exercise.

Want to join the conversation?

Sort by:

Ileri
Posted 7 years ago. Direct link to Ileri's post “Why do people always use ...”
Why do people always use rectangles, pizzas or circles to compare fractions to decimals or fractions alone?
Button navigates to signup pageComment on Ileri's post “Why do people always use ...”
(22 votes)
Answer
- Eva Coolguy
  Posted 5 years ago. Direct link to Eva Coolguy's post “I agree with Benny C beca...”
  I agree with Benny C because we see pizzas all the time and our desks are rectangles.
  BUT DON'T GO AROUND VISULIZIN' PIZZAS DON'T EAT ZEM EITHER
  Button navigates to signup page
  (1 vote)
Dheeku
Posted 6 years ago. Direct link to Dheeku's post “you can remember comparin...”
you can remember comparing fractions by cross multiplying like this 3/5 ----- 5/3
5x5=25 and 3x3=9 so you know that 5/3 is bigger !
Button navigates to signup pageButton navigates to signup page
(6 votes)
Answer
- vhtidwell
  Posted 6 years ago. Direct link to vhtidwell's post “Another way is to notice ...”
  Another way is to notice that the numerator is greater than the denominator in 5/3 but not in 3/5!
  Button navigates to signup page
  (8 votes)
carlisledorothyfisher
Posted 7 years ago. Direct link to carlisledorothyfisher's post “Do you have to do it or c...”
Do you have to do it or can you just look at the halves?
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(7 votes)
Answer
- Alexis Potteiger
  Posted 5 years ago. Direct link to Alexis Potteiger's post “cross multiplying is an e...”
  cross multiplying is an easier and faster way to do it. All you do is multiply one denominator by the numerator on the other fraction and put that number next to it and which ever side is bigger that fraction is greater. But remember MULTIPLY UP!
  Button navigates to signup page
  (1 vote)
ajsharma14
Posted 6 years ago. Direct link to ajsharma14's post “Can you compare mixed num...”
Can you compare mixed numbers with unlike denominators?
Button navigates to signup pageButton navigates to signup page
(2 votes)
Answer
- Goose
  Posted 6 years ago. Direct link to Goose's post “Yes you can! Those proble...”
  Yes you can! Those problems will probably come in 4th and 5th grade. For example, 1/2 + 2 3/4 is a real problem. It equals 3 1/4.
  Comment on Goose's post “Yes you can! Those proble...”
  (8 votes)
Kuang Xu
Posted 7 years ago. Direct link to Kuang Xu's post “why the big number is big...”
why the big number is bigger than the smaller one.
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(2 votes)
Answer
penacolmenaresj25
Posted 7 years ago. Direct link to penacolmenaresj25's post “What is da first fraction...”
What is da first fraction dat comes to your head, mine was 5/8
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(1 vote)
Answer
Alicia Lamecker
Posted 6 years ago. Direct link to Alicia Lamecker's post “How do you fill in the sq...”
How do you fill in the squares to make a fraction.
Button navigates to signup pageButton navigates to signup page
(1 vote)
Answer
- HuyD
  Posted 6 years ago. Direct link to HuyD's post “you can use the scratch p...”
  you can use the scratch pad or you can count and fill them in in your head.
  Button navigates to signup page
  (2 votes)
Latoya Shankle
Posted 6 years ago. Direct link to Latoya Shankle's post “still not understanding h...”
still not understanding how to get same denominator
then multip[ly by that I'm still confused
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(1 vote)
Answer
ann marie dean
Posted 6 years ago. Direct link to ann marie dean's post “what if i look't at 5/9 a...”
what if i look't at 5/9 and 3/7 and i had to compare them and i allrety now the anser without doing the work?
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(1 vote)
Answer
natalia
Posted 5 years ago. Direct link to natalia's post “how do you do this stuff ...”
how do you do this stuff because I don't get this. Someone help.
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(1 vote)
Answer