How to Subtract Fractions: A Comprehensive Guide

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Whether you’re a student struggling with math, a parent assisting their child, or a curious individual seeking to improve their knowledge, this guide on how to subtract fractions is for you. In this article, we will cover the fundamental concepts that underlie fraction subtraction, walk you through step-by-step instructions, and provide helpful tips and tricks to simplify the process. By the end of this guide, we promise that you will have a solid understanding of how to subtract fractions with ease.


Fractions are an essential part of mathematics and are widely used in everyday life, from baking to budgeting. However, subtracting fractions can be a challenging and intimidating task, especially for those who struggle with fractions in general. Therefore, learning how to subtract fractions is a fundamental skill that can make a significant difference in your mathematical abilities and problem-solving skills.

In this section, we will provide a brief explanation of what fractions are, why they are important, and the foundational concepts that you need to understand before diving into subtraction.

What are fractions?

Fractions are a way of representing parts of a whole. They consist of a numerator (the top number) and a denominator (the bottom number) separated by a line. The numerator represents the number of parts we have, while the denominator represents the whole from which those parts were taken. For example, if we have two out of five apples, we can represent this as 2/5.

Why are fractions important?

Fractions are crucial in various fields, including finance, science, engineering, and cooking. They allow us to represent non-whole quantities and quantities that fall between two whole numbers. Fractions also enable us to compare, add, subtract, multiply, and divide quantities with differing denominators, making complex calculations simpler to perform.

Fundamental concepts of fractions

Before we dive into how to subtract fractions, we need to understand some fundamental concepts. These include:

  1. The relationship between numerator and denominator
  2. Equivalent fractions
  3. Simplest form

The relationship between numerator and denominator

The numerator and denominator are inseparable; they must always be taken as a pair. Changing the numerator without changing the denominator or vice versa would alter the value represented by the fraction. For example, 2/5 and 6/15 represent the same quantity, while 2/5 and 3/7 do not.

Equivalent fractions

Equivalent fractions are fractions that represent the same quantity but are written differently. To find equivalent fractions, we multiply or divide both the numerator and the denominator by the same number.

Simplest form

Fractions are in their simplest form when the numerator and denominator have no common factors apart from 1. To simplify a fraction, we divide both the numerator and the denominator by their greatest common factor.

How to Subtract Fractions

Now that we have covered the foundational concepts let’s dive into how to subtract fractions.

Step 1: Find a Common Denominator

When subtracting fractions, we need to have a common denominator. A common denominator is a multiple of all the denominators we are subtracting.

To find a common denominator, we can either:

  1. Find the least common multiple (LCM) of the denominators
  2. Multiply the denominators and use the resulting product as the common denominator

For example, let’s say we want to subtract 2/3 from 3/4:

We can find the LCM of 3 and 4 by listing their multiples:

3: 3,6,9,12,15,18,…
4: 4,8,12,16,20,24,…

The smallest number that appears in both lists is 12; therefore, 12 is the LCM of 3 and 4. We then convert both fractions to have a denominator of 12:

2/3 = 8/12

3/4 = 9/12

Step 2: Subtract the Numerators

Once we have a common denominator, we can subtract the numerators. We subtract the numerators and put the result over the common denominator.

Using our example:

9/12 – 8/12 = 1/12

Step 3: Simplify the Result

The final step is to simplify the result if possible. In our example, 1/12 is already in its simplest form, so we don’t need to do anything else.

Frequently Asked Questions (FAQs)

Q1: Can I subtract fractions without a common denominator?

A1: No, you cannot subtract fractions without first finding a common denominator. Having different denominators means the fractions represent different quantities, and subtracting them requires making them equivalent.

Q2: Should I always simplify the result?

A2: It is recommended to simplify the result if possible to have the fraction in its simplest form.

Q3: Do fractions need to have the same numerator to subtract them?

A3: No, fractions do not need to have the same numerator to subtract them. Only the denominators need to be the same.

Q4: How can I check if my answer is correct?

A4: You can check your answer by adding the result to the original fraction. If the sum equals the original fraction, your answer is correct.

Q5: Can I use a calculator to subtract fractions?

A5: Yes, you can use a calculator to subtract fractions. However, using a calculator may not provide the same level of understanding as manually performing the calculations.

Q6: What are mixed numbers, and how do I subtract them?

A6: Mixed numbers are a combination of a whole number and a proper fraction. To subtract mixed numbers, convert them to improper fractions, find a common denominator, subtract the numerators, and simplify the result if possible.

Q7: Are negative fractions allowed?

A7: Yes, negative fractions are allowed. To subtract negative fractions, follow the same steps as subtracting positive fractions.


In conclusion, learning how to subtract fractions is essential for mastering math and solving real-world problems. By following our comprehensive guide, you can now subtract fractions with confidence and ease. Remember to follow the steps and pay attention to the foundational concepts, such as finding common denominators and simplifying fractions. Practicing regularly will help you retain these skills and become a fraction subtraction expert.

If you have any questions or need further assistance, feel free to reach out to a math tutor or teacher. Keep learning and practicing, and soon, you will be subtracting fractions like a pro.

Closing Statement with Disclaimer

This guide on how to subtract fractions aims to provide helpful tips and step-by-step instructions to make fraction subtraction easier for individuals who struggle with math. However, it is important to note that this guide is not a substitute for professional math instruction, and we do not claim that it will make everyone an expert overnight. We encourage readers to supplement this guide with additional resources and seek assistance from a teacher or tutor if needed. We also disclaim any liability for any loss or damage arising from the use of this guide, directly or indirectly.