# GRE Math : How to subtract fractions

## Example Questions

### Example Question #1 : How To Subtract Fractions

Solve for :

Explanation:

Begin by isolating the  factors:

Now, the common denominator of these two fractions is .  Therefore, multiply  by :

Now, you can subtract the left values:

Now, multiply both sides by :

### Example Question #1 : How To Subtract Fractions

Simplify:

Explanation:

Just like adding fractions, when you subtract fractions, you need to find a common denominator. For  and , the least common denominator is . In order to do your subtraction, you need to multiply appropriately to give your fractions this denominator:

Which is the same as...

Now, you can subtract the numerators and retain the denominator:

### Example Question #1 : How To Subtract Fractions

Which of the following is true?

Quantity A:

Quantity B:

The relationship between the quantities cannot be determined.

Quantity B is larger.

The two quantities are equal.

Quantity A is larger.

Quantity A is larger.

Explanation:

First, consider each quantity separately.

Quantity A

These two fractions do not have a common factor. Their common denominator is . Thus, we multiply the fractions as follows to give them a common denominator:

This is the same as:

Quantity B

The common denominator of these two values is .  Therefore, you multiply the fractions as follows to give them a common denominator:

This is the same as:

Since Quantity A is larger than  and Quantity B is a positive fraction less than , we know that Quantity A is larger without even using a calculator.

Tired of practice problems?

Try live online GRE prep today.