Number System MCQ Quiz - Objective Question with Answer for Number System - Download Free PDF

Last updated on Jun 23, 2025

Latest Number System MCQ Objective Questions

Number System Question 1:

147 in base 10 when converted to hexadecimal system will be:

  1. 8B
  2. 9A
  3. 93
  4. 83
  5. None of the above

Answer (Detailed Solution Below)

Option 3 : 93

Number System Question 1 Detailed Solution

Answer: Option 3

Explanation

Step 1: first we convert 147 to the Binary number system.

 BinaryConversion

(147)10 = (10010011)2

Step 2: Now we group 4 bits to convert the Hexadecimal number system.

1001 0011

≡ (93)16

Number System Question 2:

The decimal equivalent of a binary number 1001110 is: 

  1. 86
  2. 74
  3. 78
  4. 82
  5. None of the above

Answer (Detailed Solution Below)

Option 3 : 78

Number System Question 2 Detailed Solution

Convert binary to decimal :-

  • For binary number with n digits:
  • dn-1 ... d3 d2 d1 d0
  • The decimal number is equal to the sum of binary digits (dn) times their power of 2 (2n):
  • decimal = d0×20 + d1×21 + d2×22 + ...

 

Calculation:

Decimal equivalent of binary number 1001110 :-
=  1 × 2+ 0 x 25 + 0 x 2+ 1 x 2+ 1 x 22 + 1 x 2+ 0 x 20

= 64 + 0 + 0 + 8 + 4 + 2 + 0 = 78​

Number System Question 3:

The binary representation of 129.25 is _____ .

  1. (10000001.01)2
  2. (11000001.01)2
  3. (10000011.10)2
  4. (10000001.11)2
  5. None of the above

Answer (Detailed Solution Below)

Option 1 : (10000001.01)2

Number System Question 3 Detailed Solution

Binary to decimal conversion →

RRB JE CS 10 7Q 26thAug 2015 Shift2 Hindi images Q1a

(129)10 = (10000001)2

0.25 → 0.25 × 2 = 0.5

0.5 × 2 = 1

(0.25)10 = (.01)2

(129.25)10 = (10000001.01)2

Number System Question 4:

The Octal equivalent of the binary number 1011101011 is:

  1. 7353
  2. 1353
  3. 5651
  4. 5657
  5. None of the above

Answer (Detailed Solution Below)

Option 2 : 1353

Number System Question 4 Detailed Solution

Answer: Option 2

Explanation:

An octal Equivalent of a binary number is obtained by grouping 3 bits from right to left.

001 011 101 011
1 3 5 3


So Octal Equivalent: 1353

Important Points

Binary to Octal code

000

001

010

011

100

101

110

111

0

1

2

3

4

5

6

7

Number System Question 5:

Which of the following is the correct octal representation of the hexadecimal number 1A3?

  1. 346
  2. 124
  3. 634
  4. 643
  5. None of the above

Answer (Detailed Solution Below)

Option 4 : 643

Number System Question 5 Detailed Solution

Explanation:

Hexadecimal to Octal Conversion

Definition: Hexadecimal and octal are both positional numeral systems, widely used in computing and digital electronics. Hexadecimal (base-16) uses sixteen symbols, 0-9 and A-F, to represent values, while octal (base-8) uses eight symbols, 0-7.

To convert a hexadecimal number to its octal equivalent, it is often easiest to first convert it to binary (base-2), and then from binary to octal. This method works because both octal and hexadecimal are powers of 2 (octal is 23 and hexadecimal is 24).

Step-by-Step Solution:

Given hexadecimal number: 1A3

1. Convert Hexadecimal to Binary:

Each hexadecimal digit can be represented by a 4-bit binary number:

  • 1 (Hex) = 0001 (Binary)
  • A (Hex) = 1010 (Binary)
  • 3 (Hex) = 0011 (Binary)

So, the hexadecimal number 1A3 can be written in binary as: 0001 1010 0011

2. Group Binary Digits into Sets of Three:

Since octal is base-8 and each octal digit corresponds to 3 binary digits, we group the binary digits in sets of three, starting from the right:

  • 0001 1010 0011 (Binary)
  • 000 110 100 011 (Binary, grouped in sets of three)

3. Convert Binary Sets to Octal:

Each group of three binary digits can be converted directly to its octal equivalent:

  • 000 (Binary) = 0 (Octal)
  • 110 (Binary) = 6 (Octal)
  • 100 (Binary) = 4 (Octal)
  • 011 (Binary) = 3 (Octal)

So, the binary number 000 110 100 011 can be written in octal as: 0643

Hence, the correct octal representation of the hexadecimal number 1A3 is 643.

Important Information:

To analyze other options, let's convert the hexadecimal number 1A3 using the same method:

  • Option 1: 346
    • 346 (Octal) in binary: 011 100 110
    • Groups: 011 100 110 (Binary) = 3 4 6 (Octal)
    • Binary to Hexadecimal: 011100110 (Binary) = 1C6 (Hex)
    • 1C6 ≠ 1A3
  • Option 2: 124
    • 124 (Octal) in binary: 001 010 100
    • Groups: 001 010 100 (Binary) = 1 2 4 (Octal)
    • Binary to Hexadecimal: 001010100 (Binary) = 54 (Hex)
    • 54 ≠ 1A3
  • Option 3: 634
    • 634 (Octal) in binary: 110 011 100
    • Groups: 110 011 100 (Binary) = 6 3 4 (Octal)
    • Binary to Hexadecimal: 110011100 (Binary) = 19C (Hex)
    • 19C ≠ 1A3

Therefore, the correct option is confirmed as option 4: 643.

Top Number System MCQ Objective Questions

Binary number 101110110 is equal to decimal number _______.

  1. 468
  2. 412
  3. 374
  4. 326

Answer (Detailed Solution Below)

Option 3 : 374

Number System Question 6 Detailed Solution

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  • The correct answer is option 3, i.e., 374.
  • Binary number 101110110 is equal to decimal number 374.
  • Following method can be used to convert Binary number to Decimal number:
  1. (101110110)2 = (1 x 28) + (0 x 27) + (1 x 26) + (1 x 25) + (1 x 24) + (0 x 23) + (1 x 22) + (1 x 21) + (0 x 20)
  2. (101110110)2 = 256 + 0 + 64 + 32 + 16 + 0 + 4 + 2 + 0
  3. (101110110)2 = 374

One megabyte In base 2 (binary) Is equivalent to             .

  1. 103 bytes
  2. 104 bytes
  3. 210 bytes
  4. 220 bytes

Answer (Detailed Solution Below)

Option 4 : 220 bytes

Number System Question 7 Detailed Solution

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The correct answer is 220 bytes.

Key Points

  • 1 Megabyte is equal to 1000000 bytes (decimal).
  • 1 MB = 106 B in base 10 (SI).
  • 1 Megabyte is equal to 1048576 bytes (binary).
  • 1 MB = 220 B in base 2.
  • Byte is the basic unit of digital information transmission and storage, used extensively in information technology, digital technology, and other related fields. It is one of the smallest units of memory in computer technology, as well as one of the most basic data measurement units in programming.
  • The earliest computers were made with the processor supporting 1 byte commands, because in 1 byte you can send 256 commands. 1 byte consists of 8 bits,
  • Megabyte (MB) is a unit of transferred or stored digital information, which is extensively used in information and computer technology.
  • In SI, one megabyte is equal to 1,000,000 bytes. At the same time, practically 1 megabyte is used as 220 B, which means 1,048,576 bytes.

625e5fa7f8c06b4efbb09cf9 16544040466351

The Octal equivalent of the binary number 1011101011 is:

  1. 7353
  2. 1353
  3. 5651
  4. 5657

Answer (Detailed Solution Below)

Option 2 : 1353

Number System Question 8 Detailed Solution

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Answer: Option 2

Explanation:

An octal Equivalent of a binary number is obtained by grouping 3 bits from right to left.

001 011 101 011
1 3 5 3


So Octal Equivalent: 1353

Important Points

Binary to Octal code

000

001

010

011

100

101

110

111

0

1

2

3

4

5

6

7

The number of 1s in the binary representation of (3 ⋆ 4096 + 15 ⋆ 256 + 5 ⋆ 16 + 3) are  

  1. 8
  2. 9
  3. 10
  4. 12

Answer (Detailed Solution Below)

Option 3 : 10

Number System Question 9 Detailed Solution

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Application:

Decimal value = (3 ⋆ 4096 + 15 ⋆ 256 + 5 ⋆ 16 + 3)

It can be written as:

(2 + 1) × 212 + (8 + 4 + 2 + 20) × 28 + (4 + 1) × 24  + (2 + 1) × 20

21 × 212 + 20 × 212 + (23 + 22 + 21 + 20) × 28 + (22 + 20) × 24 + (21 + 20) × 20

This can be written as:

213 + 212 + 211 + 210 + 29 × 28 + 26 + 24 + 21 + 20

The binary representation will be:

(11111101010011)2

The 12th digit in standard hexadecimal system is equal to:

  1. D
  2. B
  3. A
  4. C

Answer (Detailed Solution Below)

Option 2 : B

Number System Question 10 Detailed Solution

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Mistake Points
The question is asking for the 12th Digit in Hexadecimal representation, i.e. 0 will be the first digit, 1 will be the second, and so on.

The correct answer is (option 2) i.e. B

Explanation:

Digits in hexadecimal number systems are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F. Therefore, the total number of different digits in hexadecimal number systems is 16.

Hence 12th digit in the hexadecimal system is B. And it is equivalent to 11 for Decimal and 1011 for the Binary number system,

Important Points

  • Digits in decimal number systems are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. Therefore, number of different digits in decimal number systems is 10.
  • Digits in Octal number systems are 0, 1, 2, 3, 4, 5, 6, 7. Therefore, number of different digits in octal number systems is 8.
  • Digits in binary number systems are 0, 1. Therefore, number of different digits in binary number systems is 2.
  • In the standard hexadecimal system, each digit can have 16 possible values, ranging from 0 to 9 and then A to F, representing the values 10 to 15.
  • To determine the 12th digit in the standard hexadecimal system, we need to convert the number 12 from decimal to hexadecimal.
  • 12 in decimal is equal to B in hexadecimal. Therefore, the 12th digit in the standard hexadecimal system is option 4) B.

The hexadecimal system is a number system with a base of 16. It is commonly used in computing and digital systems because it provides a convenient way to represent binary numbers. In hexadecimal, the digits range from 0 to 9, and then use the letters A to F to represent values 10 to 15.

Here's a breakdown of the digits leading up to the 12th position:

  • 1st digit: 0
  • 2nd digit: 1
  • 3rd digit: 2
  • 4th digit: 3
  • 5th digit: 4
  • 6th digit: 5
  • 7th digit: 6
  • 8th digit: 7
  • 9th digit: 8
  • 10th digit: 9
  • 11th digit: A
  • 12th digit: B

Therefore, the 12th digit in the standard hexadecimal system is 'B'.

The hexadecimal equivalent of the decimal number 4096 is ____.

  1. 1000
  2. F100
  3. F0
  4. 1F0

Answer (Detailed Solution Below)

Option 1 : 1000

Number System Question 11 Detailed Solution

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Concept:

  • To convert a decimal number system to hexadecimal, we follow the successive division approach i.e. we divide the decimal number by 16 and note down the remainder.
  • Each remainder is then expressed in hexadecimal.

 

Calculation:

F1 Neha Madhu 17.10.20 D3

So, The hexadecimal equivalent of decimal number 4096 is 1000. 

Excess - 3 - code is also known as

  1. Weighted code
  2. Cyclic redundancy code
  3. Self-complementing code
  4. Algebraic code

Answer (Detailed Solution Below)

Option 3 : Self-complementing code

Number System Question 12 Detailed Solution

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Excess - 3 - code is also known as self-complementing code which means 1's complement of an excess - 3 number is the excess - 3 code for the 9's complement of the corresponding decimal number.

Example:

1  in binary is 0001

excess 3 code is 0001 + 0011 = 0100

1's complement of the above code is 1011 which is 11 

11 is excess 3 code for 8

and 9's complement of 1 is 8

26 June 1

Decimal

Excess – 3 code

Binary

Gray code

Octal

0

0011

0000

0000

000

1

0100

0001

0001

001

2

0101

0010

0011

010

3

0110

0011

0010

011

4

0111

0100

0110

100

5

1000

0101

0111

101

6

1001

0110

0101

110

7

1010

0111

0100

111

8

1011

1000

1100

001 000

Find x = ?

If (356)8 = (x)16

  1. EA
  2. A8
  3. 7E
  4. EE

Answer (Detailed Solution Below)

Option 4 : EE

Number System Question 13 Detailed Solution

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The correct answer is option 4.

Concept:

Hexadecimal number system:

The hexadecimal number system is a kind of number system with a base value of 16 characters. It is also spelled 'hex' at times. Only 16 symbols are used to represent hexadecimal values. These are the values or symbols: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, and F. Each number corresponds to a decimal value.

Octal Number System:

The Octal Number System has an eight-digit basis and employs numbers ranging from 0 to 7. When paired in pairs of three, octal numbers are commonly represented as binary numbers in the number system.

Explanation:

The given data,

If (356)8 = (x)16

Convert the octal number to binary and then convert it into Hexa decimal.

3= 011

5= 101

6= 110

(011 101 110)2= (0 1110 1110)2

1110= E

(0 E E)16

Hence the correct answer is EE.

Alternate Method The given data,

If (356)8 = (x)16

Convert the octal number to decimal and then convert it into Hexa decimal.

(356)8 =(3 x 82+ 5 x 81+6 x 80)10

(356)8 =(238)10

(356)8 =(238)10 =(EE)16

Which type of number system is represented by base 8?

  1. Decimal 
  2. Binary 
  3. Octal 
  4. hexadecimal 

Answer (Detailed Solution Below)

Option 3 : Octal 

Number System Question 14 Detailed Solution

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Number System

The octal number system is represented by base 8.

Number System

Base

Maximum no. of bits

Range

Binary

2

2

0-1

Decimal

10

4

0-9

Octal

8

3

0-7

Hexadecimal

16

4

0-15

What is the binary number for decimal number 9?

  1. 1100
  2. 1001
  3. 0111
  4. 1011

Answer (Detailed Solution Below)

Option 2 : 1001

Number System Question 15 Detailed Solution

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The number system is a way to represent or express numbers. You have heard of various types of number systems such as the whole numbers and the real numbers. But in the context of computers, we define other types of number systems. They are:

  • The decimal number system
  • The binary number system
  • The octal number system and
  • The hexadecimal number system

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Binary Number System:

  1. A binary number system is one of the four types of number system. 
  2. In computer applications, where binary numbers are represented by only two symbols or digits, i.e. 0 (zero) and 1(one). 
  3. The binary numbers here are expressed in the base-2 numeral system. 
  4. For example, (101)2 is a binary number. Each digit in this system is said to be a bit.

Here we will show you step-by-step how to convert the decimal number 9 to binary.

Step 1) Divide 9 by 2 to get the Quotient. Keep the Whole part for the next step and set the Remainder aside.
Step 2) Divide the Whole part of the Quotient from Step 1 by 2. Again, keep the Whole part and set the Remainder aside.
Step 3) Repeat Step 2 above until the Whole part is 0.
Step 4) Write down the Remainders in reverse order to get the answer to 9 as a binary.

Important Points

Here we will show our work so you can follow along:
 

Decimal Number

Operation 

Quotient

Remainder

Binary Number

9

÷ 2

4

1

1

4

÷ 2

2

0

01

2

÷ 2

1

0

001

1

÷ 2

0

1

1001

Therefore, Binary equivalent of decimal number 9 is 1001.

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