Number System: “All digits are numbers but all numbers are not digits”- Explain.
“Tally is a non-positional number system”- Explain.
Why is the number (11)10 called a positional number? [Jessore Board-2017]
What kind of number is 10101 in the number system? Explain
What type of number is 988 in the number system? Explain.
What kind of number is 5D? Explain [Cumilla Board-2017]
Is the number (298)8 correct?- Explain. [Sylhet Board-2016]
Explain the base of the number system.
Explain the 3-based number system. [A-Set: Dhaka, Jessore, Sylhet and Dinajpur Board-2018]
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Read More# Third Chapter

## HSC ICT Chapter 3 : Knowledge Based Questions & Answers

How to write answers to knowledgebase questions?
The knowledgebase question is given to test the memory. That is, you can answer this part by memorizing any information from the text book. Answers should be given in one sentence or a maximum of three sentences as per the demand of the question. Mark allotted to this question is 1.
Number System: What is number?
What is digit? [Madrasa Board-2017]
What is the number system? [Jessore Board-2017, Madrasa Board-2016]
What is non-positional number system?
What is positional number system?
What is binary number system...

Read More## Adder, Half Adder, Full Adder, Full Adder implementation using Half Adder

At the end of this lesson-
1. You will be able to explain Adder circuit. 2. You will be able to describe Half Adder circuit. 3. You will be able to describe Full Adder circuit. 4. You will be able to implement Full adder circuit using Half adder circuit. 5. You will be able to explain binary adder circuit.
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An adder is a combinational circuit or digital circuit in electronics that implements or performs addition of numbers. It is mainly designed for the addition of binary number, but they can be used in various other applications like b...

Read More## Encoder and Decoder | Difference Between Encoder and Decoder

At the end of this lesson-
1. You will be able to explain encoder. 2. You will be able to describe the uses of encoder. 3. You will be able to explain decoder. 4. You will be able to describe the uses of decoder. 5. You will be able to differentiate encoder and decoder.
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What is Encoder?
An Encoder is a combinational circuit that produces a binary code equivalent to the input, which is active High. In other words, Encoder is a circuit which converts the analog signal into the digital signal. Encoders are digital circuit used for encodin...

Read More## Logic Circuit for Logic function & Logic function from Logic circuit

At the end of this lesson-
1. You will be able to implement any function. 2. You will be able to determine function from any circuit.
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Implementation of any function: The function may need to be implemented with only basic gates.
The function may need to be implemented with only universal gates.
The function may need to be implemented using any type of gates.
After simplifying the function, It may need to be implemented by basic or universal gates. The following rules or sequences are followed to implement the function...

Read More## NAND & NOR gates as Universal Gates

At the end of this lesson- You will be able to prove the universality of NAND and NOR gates.
You will be able to implement AND, OR & NOT gate using only NAND gate.
You will be able to implement AND, OR & NOT gate using only NOR gate.
You will be able to implement XOR & XNOR gate using only NAND gate.
You will be able to implement XOR & XNOR gate using only NOR gate.
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NAND gate as Universal Gate:
Implementation of NOT gate using only NAND gate Implementation of AND gate using only NAND gate: ...

Read More## Universal Gates (NAND, NOR) & Special Gates (XOR, XNOR)

At the end of this lesson- You will be able to explain compound gate.
You will be able to describe the Universal gates.
You will be able to describe NAND & NOR gates in details.
You will be able to describe the Exclusive gates in details.
You will be able to describe X-OR & X-NOR gates in details.
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Compound/Composite Gates:
A gate that is created using two or more basic gates is called a composite or compound gate. For example- AND Gate +NOT Gate = NAND Gate, OR Gate + NOT Gate = NOR Gate. Composite gates are two types. T...

Read More## Logic Gates & Basic Logic Gates (AND, OR & NOT)

At the end of this lesson- You will be able to explain logic gate.
You will be able to describe the types of logic gate.
You will be able to describe the basic gates in details.
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Logic gates:
A logic gate is a basic building block of a digital circuit, which is used to implement a Boolean function. It is an electronic circuit which makes logical decisions based on the combination of digital signals present on its inputs. It is an electronic circuit having one or more than one inputs and only one output. Types of Logic gates: Basic G...

Read More## Simplification of Boolean Expressions

At the end of this lesson- You will be able to describe the rules of simplifying the Boolean expressions.
You will be able to simplify the Boolean expressions.
You will be able to explain the importance of simplifying the Boolean expressions.
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The Boolean functions are implemented through the Logic Gates. In this case the number of logic operators in the function is less then the number of logic gates in the implementation is less. This makes implementation easier and saves money. Therefore, the Boolean functions are simpli...

Read More## De Morgan’s Theorem and Truth table

At the end of this lesson- You will be able to explain De Morgan's Theorem.
You will be able to create truth table.
You will be able to create Boolean function from a truth table.
You will be able to prove De Morgan's theorem using truth table.
You will be able to prove any Boolean equation using truth table.
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De Morgan’s Theorem
Mathematician De Morgan discovered two theorems for Boolean function simplification. First Theorem: It states that the complement of logical OR of at least two Boolean variables is equal to the logical AN...

Read More## Boolean Algebra, Boolean Postulates and Boolean Theorems

At the end of this lesson- You will be able to explain the characteristics of Boolean Algebra.
You will be able to explain Boolean variable, constant and complement.
You will be able to explain Boolean postulate and Duality Principle.
You will be able to explain different Boolean Theorems.
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Boolean Algebra:
Boolean Algebra is an algebra, which deals with binary numbers & binary variables. Boolean Algebra is used to analyze and simplify the digital (logic) circuits. It is also called as Binary Algebra or logical Algebra or Switching...

Read More## Code | BCD | EBCDIC | ASCII | Unicode

At the end of this lesson- You will be able to explain the concept of code.
You will be able to explain BCD code.
You will be able to explain alphanumeric code (EBCDIC, ASCII, Unicode).
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In the computer system, digits, numbers, letters or special symbols are represented by a specific group of binary bits. This group is also called as binary code. The binary code is represented by the number as well as alphanumeric letter.
Advantages of Binary Code
Following is the list of advantages that binary code offers. Binary codes ar...

Read More## Signed Number | 1’s Compliment Form | 2’s Complement Form

At the end of this lesson- You will be able to explain the concept of signed number.
You will be able to explain the different methods of representing signed number in computer system.
You will be able to do addition and subtraction of signed number using 2's complement form.
You will be able to explain basic concept of register.
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In general, we represent the positive (unsigned) numbers without any sign indication and negative numbers with ‘minus’ (negative sign) sign before them. But these are not applicable for computing in the digi...

Read More## Binary Addition | Octal Addition | Hexadecimal Addition

At the end of this lesson-
1. You will be able to do addition in different number systems.
2. You will be able to do Subtraction in different number systems.
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Addition of different number system:
Addition of decimal numbers: 1. If summation of decimal digits is equal or more than the base of decimal number system, subtract 10(base) from summation( continue subtraction until summation comes to less than 10 ) 2. Carry is how many times subtraction is occurred Example: Addition of (5689)10 and (7989)10 Addition of octal numbers:
...

Read More## Binary to Octal | Binary to Hexadecimal | Octal to Binary | Hexadecimal to Binary

At the end of this lesson-
1. You will be able to convert Octal & Hexadecimal to Binary Number system.
2. You will be able to convert Binary to Octal & Hexadecimal Number system.
3. You will be able to convert Octal to Hexadecimal Number system.
4. You will be able to convert Hexadecimal to Octal Number system.
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Conversion among Non-Decimal that means Binary, Octal & Hexadecimal Number Systems:
Step-01: Convert the number from any base to base 10.
Step-02: Convert the number from base 10 to any base.
That is, in case of non-decimal n...

Read More## Binary to Decimal | Octal to Decimal | Hexadecimal to Decimal

At the end of this lesson-
1. You will be able to convert a binary number into decimal number.
2. You will be able to convert a octal number into decimal number.
3. You will be able to convert a hexadecimal number into decimal number.
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Other Base to Decimal Number System Same Rules for Both Integer and Fractional Number-
Step-1: Multiply each digit of the given number by their positional value.
Positional value of a digit = (base of given number)position of the digit
[ In integer number, position of the digit starts from 0 (right to left) and in ...

Read More## Decimal to Binary | Decimal to Octal | Decimal to Hexadecimal

At the end of this lesson-
1. You will be able to convert a decimal number into binary number.
2. You will be able to convert a decimal number into octal number.
3. You will be able to convert a decimal number into hexadecimal number.
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Number System Conversions:
There are twelve sorts of conversions among four number systems. They are- The same rules can be divided into the following ways-
Decimal Number System to Other Base Decimal Number System to Binary Number System
Decimal Number System to Octal Number System
Decimal Number Sys...

Read More## Number System | Binary, Octal, Decimal & Hexadecimal Number

At the end of this lesson-
1. You will be able to describe the history of number.
2. You will be able to differentiate number and digit.
3. You will be able to describe the types of number system.
4. You will be able to differentiate different types of number systems.
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What is Number ?
A number is a string of one or more digits which is used to count, quantify and measure something. For example, there are 20 students in a class ; Here 20 is a number. What is Digit ?
A digit is a single numerical symbol of a number or the smalle...

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