Subtracting Fractions

Subtracting Fractions with the Same Denominator (Like Denominators)

There are 3 Simple Steps to Subtract fractions:

1- Make sure the bottom numbers (the denominators) are the same 2- Subtract the top numbers (the numerators). Put the answer over the same denominator. 3- Simplify the fraction (if needed).

Example 1: Subtract the fractions

The denominators are the same, so you can skip step1. The denominator of the answer will be 7. Subtract the numerators for the numerator in the answer. 3 - 2 = 1. The answer is. This answer is already reduced, so you can skip step 3.

All you have to do is to subtract the numerators.
And it is always a good idea to make your result "nice" by converting it to a mixed number and simplifying if possible.

Example 2: Subtract the fractions and reduce your answer.



Subtracting Fractions with Different Denominators (Unlike Denominators)

1- Find the Least Common Denominator (LCD) of the fractions

2- Rename the fractions to have the LCD

3- Subtract the numerators of the fractions

4- Simplify the Fraction (if needed).


Example 1: Subtract the fractions


The denominators are different, so you must build each fraction to a form where they both have the same denominator.

Since both 5 and 15 will divide evenly into 15, build both fractions to a denominator of 15.

Build the fraction 3 / 5 to an equivalent fraction whose denominator is 15.

Subtract the numerators to get the numerator in the answer.

This answer is already reduced, so you can skip step 4.

Example 2 : Subtract the fractions and reduce your answer.

The denominators are different, so you must build each fraction to a form where they both have the same denominator. Rewrite the problem with both denominators factored.

The common denominator will have to have factors 2, 5, and 7. Build each fraction so that each denominators has these three factors.

Simplify the answer.


Subtracting Mixed Numbers with the same Denominator

How to subtract two mixed numbers whose fractions have the same denominator:

- Subtract the numerators of the two fractions

- Place that difference over the common denominator.

- Subtract the integer portions of the two mixed numbers

- If subtracting the fractional parts created a mixed number then subtract its integer portion to the difference.


Example 1: 6 4/5 - 2 2/5= ?



Example 2: Subtract the fractions 6 6/7 - 3 5/7= ?


- Subtract the fractional part of the mixed numbers
- Subtract the integer portions of the mixed numbers
- Subtract the integer from the difference of the fractions