Number Systems and Codes Questions and Answers

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Number Systems and Codes Questions with Answers form the foundation of digital electronics reasoning and aptitude exams. This topic includes binary, octal, decimal, and hexadecimal number conversions, along with coding systems like Gray, ASCII, and BCD. Competitive exams such as GATE, DRDO, and ISRO often test candidates’ logical understanding of number representation and digital computation. Practicing reasoning questions and answers with step-by-step solutions builds numerical reasoning and circuit analysis confidence. Each question is structured to test clarity on base conversions, weighted codes, and arithmetic operations. With these aptitude-based questions, you can easily master the numerical logic behind digital systems. Download the PDF and start your reasoning test practice online today.

Number Systems and Codes

Showing 10 of 146 questions

51. The binary number 11101011000111010 can be written in hexadecimal as ________.

  • DD63A16
  • 1D63A16
  • 1D33A16
  • 1D63116
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52. Which of the following is an invalid BCD code?

  • 0011
  • 1101
  • 0101
  • 1001
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53. What decimal number does 25 represent?

  • 10
  • 31
  • 25
  • 32
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54. Convert the Gray code 1011 to binary

  • 1011
  • 1010
  • 0100
  • 1101
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55. Determine the decimal equivalent of the signed binary number 11110100 in 1's complement.

  • 116
  • –12
  • –11
  • 128
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56. What is the difference between binary coding and binary-coded decimal?

  • BCD is pure binary.
  • Binary coding has a decimal format.
  • BCD has no decimal format.
  • Binary coding is pure binary.
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57. Convert the following decimal number to BCD.

  • 011100100001
  • 111010001
  • 001010111
  • 000100100111
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58. Digital electronics is based on the ________ numbering system.

  • decimal
  • octal
  • binary
  • hexadecimal
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59. An informational signal that makes use of binary digits is considered to be:

  • solid state
  • digital
  • analog
  • non-oscillating
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60. The 1's complement of 10011101 is ________.

  • 01100010
  • 10011110
  • 01100001
  • 01100011
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