Binary Multiplication - 3.5 | 3. Digital Arithmetic - Part B | Digital Electronics - Vol 1
K12 Students

Academics

AI-Powered learning for Grades 8–12, aligned with major Indian and international curricula.

Academics
Professionals

Professional Courses

Industry-relevant training in Business, Technology, and Design to help professionals and graduates upskill for real-world careers.

Professional Courses
Games

Interactive Games

Fun, engaging games to boost memory, math fluency, typing speed, and English skillsβ€”perfect for learners of all ages.

games

Interactive Audio Lesson

Listen to a student-teacher conversation explaining the topic in a relatable way.

Understanding Basic Rules of Binary Multiplication

Unlock Audio Lesson

Signup and Enroll to the course for listening the Audio Lesson

0:00
Teacher
Teacher

Today, we're going to explore binary multiplication. Can anyone tell me what happens when we multiply two zeros in binary?

Student 1
Student 1

Zero times zero is zero!

Teacher
Teacher

Correct! Now, what about one times one?

Student 2
Student 2

That would be one.

Teacher
Teacher

Exactly. So, the fundamental rules we need to remember are: 0 times anything is 0, and 1 times 1 is 1. Can someone summarize the four basic rules?

Student 3
Student 3

0 times 0 is 0, 0 times 1 is 0, 1 times 0 is 0, and 1 times 1 is 1.

Teacher
Teacher

Great job! Remember this as we move into more complex algorithms for multiplication.

Repeated Left-Shift and Add Algorithm

Unlock Audio Lesson

Signup and Enroll to the course for listening the Audio Lesson

0:00
Teacher
Teacher

Now let's discuss the repeated left-shift and add algorithm. Can anyone explain what we mean by 'partial products'?

Student 4
Student 4

I think they are the individual results we get when we multiply the multiplicand by each bit of the multiplier.

Teacher
Teacher

Excellent! Each time we multiply by a bit, if it’s a one, we keep it; if it’s zero, we can disregard it. How do we arrange those partial products in binary?

Student 1
Student 1

We shift them left as we move to the next bit in the multiplier.

Teacher
Teacher

"Precisely! This left-shift is crucial. For example, multiplying 23 by 6 would yield:

Repeated Add and Right-Shift Algorithm

Unlock Audio Lesson

Signup and Enroll to the course for listening the Audio Lesson

0:00
Teacher
Teacher

Next, we’ll cover the repeated add and right-shift algorithm. Can someone explain how this differs from the one we just discussed?

Student 2
Student 2

In this method, we start with a zero result and add the multiplicand based on whether the multiplier bit is 1 or 0?

Teacher
Teacher

Exactly! After each addition, we shift the result right. Why do you think this algorithm is preferred by microprocessors?

Student 3
Student 3

Because it’s easier to implement without needing many shifts.

Teacher
Teacher

Spot on! Let’s walk through an example of multiplying 23 by 6 using this algorithm. We can clearly see how the shifts and adds play out.

Introduction & Overview

Read a summary of the section's main ideas. Choose from Basic, Medium, or Detailed.

Quick Overview

Binary multiplication uses basic rules similar to binary addition, utilizing algorithms such as repeated left-shift and add or repeated add and right-shift.

Standard

Binary multiplication is performed based on the AND gate function, where the multiplication of two bits results in basic outcomes. Two primary algorithms are utilized for larger bit binary multiplications: the repeated left-shift and add algorithm and the repeated add and right-shift algorithm, which aid in practical implementation for microprocessors.

Detailed

Binary Multiplication

Binary multiplication is fundamental to digital arithmetic, applying logical operations akin to those performed in addition but adapted for binary systems. This section elucidates the basic rules governing binary multiplication and introduces two algorithms facilitating multiplication of multi-bit binary numbers.

Basic Rules of Binary Multiplication

The binary multiplication rules directly stem from the workings of an AND gate. The essential rules governing multiplication in binary are:
1. 0 Γ— 0 = 0
2. 0 Γ— 1 = 0
3. 1 Γ— 0 = 0
4. 1 Γ— 1 = 1

Multiplication Algorithms

1. Repeated Left-Shift and Add Algorithm

This method mirrors decimal multiplication in the way it operates:
- Each partial product corresponding to each bit in the multiplier is generated.
- The first partial product is formed by multiplying the multiplicand by the least significant bit (LSB) of the multiplier. For each subsequent LSB, the partial product is shifted one place to the left, and addition accumulates these products, resulting in the final binary product.

2. Repeated Add and Right-Shift Algorithm

In contrast to the left-shift method, this algorithm employs:
- An all-zero initial result approximately corresponding to the binary size of the multiplicand.
- If the LSB of the multiplier is 1, the multiplicand is added; if it is 0, nothing is added. The resultant binary string is then shifted right, and the process continues until all bits of the multiplier have been processed.

When both multiplicand and multiplier possess different signs, the resultant product carries a negative sign; otherwise, it remains positive. This highlights the importance of understanding both algorithms and their correct applications in computer arithmetic.

Youtube Videos

Introduction to Number Systems
Introduction to Number Systems

Audio Book

Dive deep into the subject with an immersive audiobook experience.

Basic Rules of Binary Multiplication

Unlock Audio Book

Signup and Enroll to the course for listening the Audio Book

The basic rules of binary multiplication are governed by the way an AND gate functions when the two bits to be multiplied are fed as inputs to the gate. The basic rules of multiplication are listed as follows:
1. 0Γ—0=0.
2. 0Γ—1=0.
3. 1Γ—0=0.
4. 1Γ—1=1.

Detailed Explanation

In binary multiplication, the rules mirror the behavior of an AND gate. This means:
- If both bits are 0, the result is 0.
- If one bit is 1 and the other is 0, the result is 0.
- If one bit is 0 and the other is 1, the result is again 0.
- If both bits are 1, the result is 1. These fundamental rules form the basis for multiplying larger binary numbers.

Examples & Analogies

Think of binary multiplication like a light switch. When both switches (representing the bits) are off (0), the light (result) stays off (0). If one switch is on (1) and the other is off (0), the light also stays off (0). The light only turns on (1) when both switches are on (1).

Repeated Left-Shift and Add Algorithm

Unlock Audio Book

Signup and Enroll to the course for listening the Audio Book

One of the methods for multiplication of larger-bit binary numbers is similar to what we are familiar with in the case of decimal numbers. This is called the β€˜repeated left-shift and add’ algorithm. In this method of binary multiplication, the end-product is the sum of several partial products, with the number of partial products being equal to the number of bits in the multiplier binary number. Each successive partial product after the first is shifted one digit to the left with respect to the immediately preceding partial product. The addition of all partial products gives the final answer.

Detailed Explanation

In this algorithm, multiplication resembles how we multiply in decimal. You create several partial products based on the bits in the multiplier. Here's how it works step-by-step:
1. Start by taking the least significant bit (LSB) of the multiplier.
2. If LSB is 1, write down the multiplicand. If it's 0, write down a row of zeros.
3. For the next bits, shift the results one position to the left and repeat the process.
4. Finally, add all the partial products together to get the final answer. If the multiplicand and multiplier have opposite signs, the result will be negative; otherwise, it'll be positive.

Examples & Analogies

Imagine you are stacking blocks (partial products). If you want to multiply 3 blocks by 2 blocks in binary, you'd first lay down one set of blocks for each 1 in the multiplier. For each higher place value in the multiplier (like moving left), you'll shift the stack over one space, just like putting a new block on a higher level.

Repeated Add and Right-Shift Algorithm

Unlock Audio Book

Signup and Enroll to the course for listening the Audio Book

Microprocessors and microcomputers, however, use what is known as the 'repeated add and right-shift' algorithm to do binary multiplication as it is comparatively much more convenient to implement than the 'repeated left-shift and add' algorithm. The multiplication process starts with writing an all β€˜0’ bit sequence, with the number of bits equal to the number of bits in the multiplicand. This sequence is added to another same-sized bit sequence, which is the same as the multiplicand if the LSB of the multiplier is a β€˜1’, and an all β€˜0’ sequence if it is a β€˜0’. The result of the first addition is shifted one bit position to the right, and the bit shifted out is recorded. The process continues until all multiplier bits are exhausted.

Detailed Explanation

In the repeated add and right-shift method, you begin by initializing a result with all zeros. Here’s how it works:
1. For each bit of the multiplier, check if it's 1 or 0. If 1, add the multiplicand to the result; if 0, add nothing.
2. Regardless, shift the current result one bit to the right each time.
3. Continue this until you've processed all bits of the multiplier. The final result will reflect whether the inputs were positive or negative based on their signs.

Examples & Analogies

Think of this like taking turns in a game. Each player’s turn represents a bit in the multiplier. When it’s your turn (1), you add points (the multiplicand) to your score (result); if it's not your turn (0), you keep the score the same. After your turn ends, imagine stepping backward (right-shifting) in the line of players until everyone has had a turn.

Mixed Binary Multiplication

Unlock Audio Book

Signup and Enroll to the course for listening the Audio Book

Binary multiplication of mixed binary numbers is done by performing multiplication without considering the binary point. Starting from the LSB, the binary point is then placed after n bits, where n is equal to the sum of the number of bits in the fractional parts of the multiplicand and multiplier.

Detailed Explanation

When multiplying numbers with both integer and fractional parts in binary, treat them as whole numbers first. Here’s how:
1. Perform the multiplication as if the numbers were whole numbers by ignoring the binary point.
2. After getting the result, calculate the placement of the binary point by counting the total number of bits in the fractional parts from both the multiplicand and multiplier.
3. Place the binary point in the result accordingly to reflect the correct value.

Examples & Analogies

Consider a recipe that calls for fractions of ingredients. When you multiply two fractions, you first multiply the numerators and denominators separately before simplifying. Similarly, in binary multiplication, you combine the numbers first, then adjust for the fractional parts (like converting back to easy-to-understand measurements).

Definitions & Key Concepts

Learn essential terms and foundational ideas that form the basis of the topic.

Key Concepts

  • Binary Multiplication: Refers to the process of multiplying binary numbers based on fixed logical rules.

  • AND Gate: An electronic circuit responsible for computing the multiplication of two binary digits.

  • Repeated Left-Shift and Add: An algorithm to perform binary multiplication by shifting and adding based on bit positions.

  • Repeated Add and Right-Shift: A different algorithm utilized in microprocessors for efficient binary multiplication.

Examples & Real-Life Applications

See how the concepts apply in real-world scenarios to understand their practical implications.

Examples

  • Multiplying 23 (10111 in binary) by 6 (110 in binary), resulting in 138 (10001010 in binary) using the left-shift method.

  • Using the right-shift method on the same multiplicands, highlighting the difference in processes but arriving at the same endpoint.

Memory Aids

Use mnemonics, acronyms, or visual cues to help remember key information more easily.

🎡 Rhymes Time

  • When one meets zero, the result's a hero, zero's the fate, when ones congregate!

πŸ“– Fascinating Stories

  • Imagine two friends, 1 and 0, playing a game where 0 always gives up while 1 stands tall. Together they either win or lose depending on who's on the right.

🧠 Other Memory Gems

  • To remember multiplication rules: 'zero is king when no ones play.'

🎯 Super Acronyms

Remember M.A.W. for Multiplication Always Works

  • M: for Multiply
  • A: for AND
  • W: for the win of 1.

Flash Cards

Review key concepts with flashcards.

Glossary of Terms

Review the Definitions for terms.

  • Term: AND Gate

    Definition:

    An electronic component that produces a true output (1) only when all its inputs are true (1).

  • Term: Multiplicand

    Definition:

    The number that is to be multiplied.

  • Term: Multiplier

    Definition:

    The number by which the multiplicand is multiplied.

  • Term: Partial Product

    Definition:

    The intermediate results obtained during the multiplication process before summing them to form the final product.

  • Term: Shift

    Definition:

    Moving bits in a binary number to the left or right during multiplication or division.