Subtracting Negative Fractions

In the realm of mathematics, fractions often pose challenges for students, especially when negative numbers come into play.

The concept of subtracting negative fractions might initially seem daunting, but with the right approach and understanding, it can become a valuable skill for Grade 7 students.

This fundamental mathematical operation not only strengthens their grasp of fractions but also equips them with the ability to solve real-world problems involving negative quantities.

Table of Contents:

• Subtracting Negative Fractions
• Properties of Subtracting Negative Fractions
• Applying the Rule of Signs
• Solved Examples
• FAQs

Subtracting Negative Fractions

Before we dive into subtracting negative fractions, let’s revisit the basics. A negative fraction is a fraction that has a negative sign (-) in front of it. It indicates a quantity that is less than zero. It’s important to remember that a negative fraction consists of a numerator (the top number) and a denominator (the bottom number), just like any other fraction.

Subtraction is a mathematical operation that involves finding the difference between two numbers or quantities. In the context of fractions, subtracting fractions means finding the difference between their values. To subtract fractions, we need to ensure that they have the same denominator. If they don’t, we must first find a common denominator before proceeding with the subtraction.

Properties of Negative Fractions Subtraction

Subtraction is the same as addition: When subtracting a negative fraction, it is equivalent to adding a positive fraction. This property is based on the idea that subtracting a negative is the same as adding a positive. Therefore, the subtraction of negative fractions can be rewritten as the addition of positive fractions, simplifying the process.

Adding the opposite: To subtract a negative fraction, it is helpful to understand that subtracting a negative is the same as adding the opposite. By changing the sign of the negative fraction to positive, you can convert the subtraction into an addition problem.

Rule of signs: When subtracting negative fractions, the rule of signs comes into play. If there is a negative sign in front of the fraction being subtracted, it changes the sign of the fraction. This means that subtracting a negative fraction is equivalent to adding a positive fraction.

Finding a common denominator: Before subtracting fractions, it is essential to find a common denominator. This ensures that the fractions have the same base, making the subtraction operation easier. By finding a common denominator, you can add or subtract the numerators while keeping the denominator unchanged.

Simplifying the result: After subtracting the fractions, it is recommended to simplify the resulting fraction if possible. Simplification involves reducing the fraction to its lowest terms by dividing both the numerator and the denominator by their greatest common factor. This step helps to express the result in its simplest form.

Applying the Rule of Signs

When subtracting negative fractions, the rule of signs plays a crucial role. If we have a negative fraction, we can think of it as a positive fraction multiplied by -1. This means that subtracting a negative fraction is equivalent to adding a positive fraction. It’s essential to keep this in mind when performing the subtraction operation.

Step-by-Step Process:

To subtract negative fractions, follow these steps:
a) Find a common denominator for the fractions involved.
b) Adjust the numerators based on the rule of signs.
c) Subtract the adjusted numerators while keeping the common denominator unchanged.
d) Simplify the resulting fraction if possible by reducing it to its lowest terms.

Solved Examples

Example 1: Subtract: -3/4 – (-1/4)

Step 1: Find a common denominator, which in this case is 4.

Step 2: Adjust the signs of the fractions according to the rule of signs.

-3/4 becomes -3/4 and -(-1/4) becomes +1/4.

Step 3: Subtract the adjusted numerators while keeping the common denominator unchanged.

-3/4 – (+1/4) = -3/4 – 1/4 = -4/4 = -1.

Step 4: The result, -1, is already in its simplest form, so there is no need for further simplification.

Therefore, -3/4 – (-1/4) = -1.

Example 2: Subtract: -2/3 – (-5/6)

Step 1: Find a common denominator, which in this case is 6.

Step 2: Adjust the signs of the fractions according to the rule of signs.

-2/3 becomes -2/3 and -(-5/6) becomes +5/6.

Step 3: Subtract the adjusted numerators while keeping the common denominator unchanged.

-2/3 – (+5/6) = -2/3 – 5/6.

To subtract these fractions, we need to have the same denominator. Let’s convert -2/3 to -4/6 (multiplying numerator and denominator by 2).

-4/6 – 5/6 = -9/6.

Step 4: The resulting fraction, -9/6, can be simplified. Since both the numerator and denominator are divisible by 3, we can divide them by 3.

-9/6 ÷ 3/3 = -3/2.

Therefore, -2/3 – (-5/6) = -3/2.

Example 3: Subtract: -1/2 – (-3/8)

Step 1: Find a common denominator, which in this case is 8.

Step 2: Adjust the signs of the fractions according to the rule of signs.

-1/2 becomes -1/2 and -(-3/8) becomes +3/8.

Step 3: Subtract the adjusted numerators while keeping the common denominator unchanged.

-1/2 – (+3/8) = -1/2 – 3/8.

To subtract these fractions, we need to have the same denominator. Let’s convert -1/2 to -4/8 (multiplying the numerator and denominator by 4).

-4/8 – 3/8 = -7/8.

Step 4: The result, -7/8, is already in its simplest form, so there is no need for further simplification.

Therefore, -1/2 – (-3/8) = -7/8.

Subtracting Negative Fractions FAQS

Grade 7 Science Worksheets

• Elements and Compounds
• Solar Energy
• Photosynthesis
• Electricity and Magnetism
• Law of conservation of energy
• Periodic table
• Properties of Matter
• Waves
• Energy Resources 
• Weather and Climate
• Immune, Circulatory and Digestive Systems
• Organs in Multi-cellular Organism
• Sedimentary, Igneous, and Metamorphic Rocks
• Structure of the Earth
• Law of Conservation of Mass
• Physical and Chemical Changes
• Scientific Method
• Human Digestive System
• Environmental Science
• Renewable and Non-renewable energy Resources
• Characteristics of Living Organisms
• Life Science
• Earth and Space Science
• Solar Eclipse
• Heat Technology
• Newton’s Laws of Motions
• Physical Science
• Tools, Measurement and SI Units
• Earth Atmosphere
• Interactions of Living things
• The Earth Ecosystem
• Organelles in Plant and Animal cells
• Layers of the Earth
• Cycles in Nature

Grade 7 Math Worksheets

• Fractions
• Linear equations word problems
• Statistics
• Properties of Parallel Line
• Finding slope from an equation
• Identifying Quadrilaterals
• Percent Change
• Properties of addition and multiplication
• Pythagorean Theorem
• Solving two step inequalities
• Symmetry
• Fractions to Decimals (New)
• Whole Number Exponents with Integer Bases (New)
• Adding and Subtracting Fractions (New)
• Integer Addition and Subtraction (New)
• Dividing Mixed Numbers (New)
• Basics of Coordinate Geometry (New)