Comparing Fractions By: Ms. J. Godfrey

Comparing Fractions

When you compare fractions, you use symbols.

> greater than

< less than

= equal to

How to compare fractions

There are three methods that you can use to compare fractions. Method 1: Cross multiplication

Method 2: Common denominator

Method 3: Changing the fractions to decimals then comparing the decimals. (previously taught)

Method 1: Cross multiplication

(5) 1 2 2 ____ 5

Step 1: Multiply the numerator of fraction 1 by the dominator of fraction 2.1 x 5 = 5 * Place the product above the 1st fraction.

Method 1: Cross multiplication

(5) (4) 1 2 2 ____ 5

Step 2: Multiply the numerator of fraction 2 by the dominator of fraction 1.2 x 2 = 4 * Place the product above the 2nd fraction.

Method 1: Cross multiplication

(5) (4) These are your products.

1 2

2 ___ 5

Step 3: Compare the products by placing a symbol in the middle.

*Make sure you read from left to right.

5 is _____ 4

What is the correct answer?

a) < b) > c) =

Method 2: Common Denominator

3 2

4 ___ 6

Step 1: Find the least common denominator of the given fractions.

Denominators: 4 and 6

See next slide for steps to find LCD.

Method 2: Common Denominator

How to find the least common denominator:

4 x 1 = 4 6 x 1 = 6

4 x 2 = 8 6 x 2 = 12

4 x 3 = 12 6 x 3 = 18

4 x 4 = 16 6 x 4 = 24

LCD: 12

Method 2: Common Denominator

Step 2: Compose equivalent fractions that will have the LCD.

3= ___ 3 x 3 = 9

4 12 4 x 3 12

2= ___ 2 x 2 = 4

6 12 6 x 2 12

* When composing equivalent fractions, you must divide the numerator and denominator by the same number.

Method 2: Common Denominator

Step 3: Compare the new fractions by looking at the numerator.

* Make sure to put them back in the order that they were given.

9 4 12 _>_ 12

so

3 2 4 _>_ 6