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Binary Subtraction

In digital electronics and computer systems, where all data is processed using binary numbers,combinations of 0s and 1 binary subtraction is a basic operation. Binary subtraction has its own set of basic rules, just like subtraction in the decimal system. Anybody else interested in computer science or digital logic, knowing how to perform binary subtraction is crucial. You can easily learn binary subtraction with the help of this guide, which will take you through the idea, guidelines, techniques, examples, and practice problems.

 

Table of Contents

What is Binary Subtraction?

Binary subtraction is a mathematical operation that involves subtracting one binary number from another. Just like decimal subtraction uses digits from 0 to 9, binary subtraction uses only two digits: 0 and 1. This process is crucial in digital electronics, computer systems, and microprocessor design.

The subtraction process in binary follows a set of fixed rules that are somewhat different from those of the decimal number system due to the limitation of digits (only 0 and 1).

 

Binary Subtraction Table

Minuend (A)

Subtrahend (B)

Result (A - B)

Borrow

0

0

0

0

1

0

1

0

1

1

0

0

0

1

1

1 (borrow)

In binary subtraction, the only scenario that requires a borrow is 0 - 1, which is resolved by borrowing 1 from the next significant bit, making it 10 (binary for 2). So, 10 - 1 = 1, and a borrow is recorded.

 

Binary Subtraction Rules

 To perform binary subtraction, you must understand the binary subtraction rules:

  1. 0 - 0 = 0

  2. 1 - 0 = 1

  3. 1 - 1 = 0

  4. 0 - 1 = 1 (borrow 1 from the next digit)

In rule 4, we borrow 1 from the next higher-order bit. The 0 becomes 10 (binary of 2), and then 10 - 1 = 1.

These binary subtraction rules are the core of how computers process binary data efficiently.

 

How to Subtract Binary Numbers?

Binary subtraction uses only two digits:0 and 1,but is calculated in a manner similar to decimal subtraction. Beginning with the digit on the right, you gradually apply binary subtraction rules.

Recap of Binary Subtraction Rules: 0 - 0 = 0.

  • 0 - 0 = 0

  • 1 - 0 = 1

  • 1 - 1 = 0

  • 0 - 1 = 1 (with a borrow from the next left bit)

Steps for Subtracting Binary Numbers:

  1. Align the two binary numbers by place value when writing them (just like regular subtraction).
  2. Beginning at the far right, proceed to the left.
  3. For every pair of digits, apply the binary subtraction rules.
  4. To make 10 (or 2 in decimal) if you come across 0-1, take 1 from the next higher bit.
  5. Note the outcome for every column.
  6. This is how binary subtraction questions are solved manually.

Binary Subtraction Using One’s Complement

There’s another efficient way to perform binary subtraction using One’s Complement. Computers often use this method because it’s easier to implement electronically.

Steps for One’s Complement Method:

  1. Find the one’s complement of the subtrahend.

  2. Add it to the minuend.

  3. If there is a carry, add it to the result.

  4. If there’s no carry, take the one’s complement of the result.

Example:
Subtract 0101 (5) from 1001 (9)
Minuend: 1001
Subtrahend: 0101
One’s complement of subtrahend = 1010
Add: 1001 + 1010 = 10011
Remove carry (1), result = 0011 (3 in decimal)

This is a common question in exams that test knowledge of binary subtraction using one’s complement.

 

Solved Binary Subtraction Examples

Example 1:
Subtract: 1011 – 0101

1 0 1 1

-0 1 0 1
-------------

0 1 1 0

Answer: 0110 (6 in decimal)

 

Example 2:
Subtract: 1110 – 0111

         1 1 1 0

       -   0 1 1 1

    ------------------

          1 0 0 1

Answer: 1001 (9 in decimal)

 

Example 3:
Subtract using One’s Complement: 1100 – 1010

  1. One’s complement of 1010 = 0101

  2. Add: 1100 + 0101 = 10001

  3. Drop carry and add: 0001 + 1 = 0010

Answer: 0010 (2 in decimal)

These binary subtraction examples demonstrate both direct and one's complement methods effectively.

 

Practice Binary Subtraction Questions

Practice these binary subtraction questions to improve your understanding:

Q1: Subtract 1000 – 0100
Q2: Subtract 1111 – 1011
Q3: Subtract 1101 – 0011 using one’s complement
Q4: Subtract 1010 – 1100
Q5: Subtract 1001 – 0110
Q6: Subtract 1110 – 0110 using one’s complement
Q7: Subtract 0101 – 0011
Q8: Subtract 1110 – 1011

Practice these binary subtraction questions using the binary subtraction rule or one’s complement method.

 

Binary Subtraction vs Decimal Subtraction

Feature

Binary Subtraction

Decimal Subtraction

Digits Used

0 and 1

0 to 9

Borrowing Complexity

Only from higher bits

Varies with number

Used In

Computer operations

Daily arithmetic

Calculator Needed?

Optional (for large inputs)

Optional

Remember, binary operations form the foundation of computer architecture.

 

Important Points to Remember

  • Binary subtraction is a crucial operation in computer arithmetic.

  • Understand the binary subtraction rule and the subtraction table.

  • Learn to subtract manually or using one’s complement.

  • Use binary calculator tools for quick verification.

  • Solve binary subtraction examples regularly for mastery.

  • Practice plenty of binary subtraction questions to build speed and accuracy.

Conclusion

Understanding binary subtraction is vital for any student learning digital logic, computer science, or electrical engineering. Whether you're subtracting manually using the binary subtraction rule, using one’s complement, or using a binary calculator, the concept remains central to all digital computation.

By practicing with binary subtraction examples and solving plenty of binary subtraction questions, you'll gain the confidence and skill required to work fluently with binary numbers. Make it a point to master this topic through regular practice.

 

Related Links

Binary Number System - Discover how binary numbers work and their importance in computing.

Binary to Decimal Conversion - Learn step-by-step how to convert binary numbers into decimal form with simple examples.

Decimal Numbers to Binary Numbers - Learn how to convert decimal numbers to binary step by step.

 

Frequently Asked Questions on Binary Subtraction

1. How to do subtraction of binary?

To subtract in binary, follow these rules:

  • 0 - 0 = 0

  • 1 - 0 = 1

  • 1 - 1 = 0

  • 0 - 1 = 1 (with borrow)

Start from the rightmost digit and subtract each bit. Borrow from the next left bit if needed.

 

2. What is the subtraction of 101111 – 010101?

Step-by-step subtraction:

 101111  

- 010101  

–––––––––––

  011010  

Answer: 011010 (26 in decimal)

 

3. What is the binary subtraction of 100101 – 011110?

Step-by-step subtraction:

 100101  

- 011110  

–––––––––––

  000111  

Answer: 000111 (7 in decimal)

 

4. What is 0101 in binary?

0101 is already a binary number. It equals 5 in decimal.

 

5. How to subtract in binary?

To subtract binary numbers:

  1. Line up the two binary numbers.

  2. Apply the binary subtraction rules to each column.

  3. Borrow from the next left bit when 0 is subtracted by 1.

  4. Write the result from right to left.

You can also use a binary calculator or one’s complement method for efficient subtraction.

 

Explore binary subtraction and other fun math concepts with Orchids The International School!



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