Learn how to figure out which fraction is bigger or smaller using common denominators and benchmarks.
Imagine you and your friends are sharing giant pizzas. If you get of a pizza and your friend gets , who actually has more to eat? It’s hard to tell just by looking, but math gives us a secret superpower to know for sure!
When we compare fractions, we are looking at two things: how many pieces we have (the numerator) and how big those pieces are (the denominator). If the denominators are the same, it's easy! is bigger than because 5 pieces are more than 3 pieces of the same size. But what if the denominators are different? That's like comparing big slices of watermelon to tiny slices of an apple. To compare them fairly, we often try to find a common denominator, which means making the slices the same size so we can just count the pieces.
Compare and .
1. Look at the denominators. They are both , so the pieces are the same size. 2. Look at the numerators. is less than . 3. Write the answer: .
Quick Check
If two fractions have the same denominator, which one is larger?
Answer
The fraction with the larger numerator is larger.
Sometimes you don't need to do any hard math to compare fractions. You can use a benchmark, like . A benchmark is a familiar number used as a point of reference. To see if a fraction is bigger or smaller than , look at the denominator and ask: 'What is half of this number?' If the numerator is more than half, the fraction is greater than . If it's less, the fraction is smaller than . This is a fast way to compare two fractions that are on opposite sides of the middle!
Compare and .
1. Use as a benchmark. 2. For : Half of is . Since is less than , . 3. For : Half of is . Since is more than , . 4. Since is less than half and is more than half, .
Quick Check
Is greater than or less than ?
Answer
Less than .
When you have three or more fractions to put in order, you combine your skills. First, check if any are smaller than and if any are larger. This helps you group them. If two fractions are both larger than , you might need to find a common denominator to see which one wins. To find a common denominator, you find a number that both denominators can multiply into. Once they look the same on the bottom, you can line them up from least to greatest easily.
Order , , and from least to greatest.
1. Use the benchmark . 2. We know is less than (because half of 4 is 2). 3. We know is more than (because half of 6 is 3). 4. Now we can place them: The smallest is , the middle is , and the largest is . 5. Final Order: .
Which symbol correctly completes this statement: ?
Which of these fractions is greater than ?
True or False: is larger than .
Review Tomorrow
In 24 hours, try to explain to someone why is smaller than without using a calculator.
Practice Activity
Next time you are in the kitchen, look at measuring cups. Try to order , , and from smallest to largest by looking at their sizes!