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Signed eight-bit values

Set 3 of 8 · 32 worked questions. Predict your result before expanding the solution.

These worked traces are meant to build fluency through controlled variation. If several answers feel identical, try the next difficult value and look for the point where a carry, sign, branch, or selected memory address changes the outcome.

Foundations · Problem 0065

Interpret 01000000 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01000000 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 64.
  6. Add those contributions: 0 + 64 = 64.
  7. As an unsigned pattern, the same eight bits represent 64.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10111111; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 11000000.
  11. Answer: signed(01000000) = 64.

Final answer: 64

Foundations · Problem 0066

Interpret 01000001 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01000001 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 65.
  6. Add those contributions: 0 + 65 = 65.
  7. As an unsigned pattern, the same eight bits represent 65.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10111110; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10111111.
  11. Answer: signed(01000001) = 65.

Final answer: 65

Foundations · Problem 0067

Interpret 01000010 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01000010 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 66.
  6. Add those contributions: 0 + 66 = 66.
  7. As an unsigned pattern, the same eight bits represent 66.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10111101; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10111110.
  11. Answer: signed(01000010) = 66.

Final answer: 66

Foundations · Problem 0068

Interpret 01000011 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01000011 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 67.
  6. Add those contributions: 0 + 67 = 67.
  7. As an unsigned pattern, the same eight bits represent 67.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10111100; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10111101.
  11. Answer: signed(01000011) = 67.

Final answer: 67

Foundations · Problem 0069

Interpret 01000100 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01000100 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 68.
  6. Add those contributions: 0 + 68 = 68.
  7. As an unsigned pattern, the same eight bits represent 68.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10111011; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10111100.
  11. Answer: signed(01000100) = 68.

Final answer: 68

Foundations · Problem 0070

Interpret 01000101 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01000101 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 69.
  6. Add those contributions: 0 + 69 = 69.
  7. As an unsigned pattern, the same eight bits represent 69.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10111010; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10111011.
  11. Answer: signed(01000101) = 69.

Final answer: 69

Foundations · Problem 0071

Interpret 01000110 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01000110 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 70.
  6. Add those contributions: 0 + 70 = 70.
  7. As an unsigned pattern, the same eight bits represent 70.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10111001; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10111010.
  11. Answer: signed(01000110) = 70.

Final answer: 70

Foundations · Problem 0072

Interpret 01000111 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01000111 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 71.
  6. Add those contributions: 0 + 71 = 71.
  7. As an unsigned pattern, the same eight bits represent 71.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10111000; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10111001.
  11. Answer: signed(01000111) = 71.

Final answer: 71

Foundations · Problem 0073

Interpret 01001000 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01001000 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 72.
  6. Add those contributions: 0 + 72 = 72.
  7. As an unsigned pattern, the same eight bits represent 72.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10110111; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10111000.
  11. Answer: signed(01001000) = 72.

Final answer: 72

Foundations · Problem 0074

Interpret 01001001 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01001001 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 73.
  6. Add those contributions: 0 + 73 = 73.
  7. As an unsigned pattern, the same eight bits represent 73.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10110110; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10110111.
  11. Answer: signed(01001001) = 73.

Final answer: 73

Foundations · Problem 0075

Interpret 01001010 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01001010 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 74.
  6. Add those contributions: 0 + 74 = 74.
  7. As an unsigned pattern, the same eight bits represent 74.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10110101; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10110110.
  11. Answer: signed(01001010) = 74.

Final answer: 74

Foundations · Problem 0076

Interpret 01001011 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01001011 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 75.
  6. Add those contributions: 0 + 75 = 75.
  7. As an unsigned pattern, the same eight bits represent 75.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10110100; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10110101.
  11. Answer: signed(01001011) = 75.

Final answer: 75

Foundations · Problem 0077

Interpret 01001100 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01001100 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 76.
  6. Add those contributions: 0 + 76 = 76.
  7. As an unsigned pattern, the same eight bits represent 76.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10110011; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10110100.
  11. Answer: signed(01001100) = 76.

Final answer: 76

Foundations · Problem 0078

Interpret 01001101 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01001101 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 77.
  6. Add those contributions: 0 + 77 = 77.
  7. As an unsigned pattern, the same eight bits represent 77.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10110010; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10110011.
  11. Answer: signed(01001101) = 77.

Final answer: 77

Foundations · Problem 0079

Interpret 01001110 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01001110 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 78.
  6. Add those contributions: 0 + 78 = 78.
  7. As an unsigned pattern, the same eight bits represent 78.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10110001; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10110010.
  11. Answer: signed(01001110) = 78.

Final answer: 78

Foundations · Problem 0080

Interpret 01001111 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01001111 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 79.
  6. Add those contributions: 0 + 79 = 79.
  7. As an unsigned pattern, the same eight bits represent 79.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10110000; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10110001.
  11. Answer: signed(01001111) = 79.

Final answer: 79

Foundations · Problem 0081

Interpret 01010000 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01010000 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 80.
  6. Add those contributions: 0 + 80 = 80.
  7. As an unsigned pattern, the same eight bits represent 80.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10101111; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10110000.
  11. Answer: signed(01010000) = 80.

Final answer: 80

Foundations · Problem 0082

Interpret 01010001 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01010001 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 81.
  6. Add those contributions: 0 + 81 = 81.
  7. As an unsigned pattern, the same eight bits represent 81.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10101110; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10101111.
  11. Answer: signed(01010001) = 81.

Final answer: 81

Foundations · Problem 0083

Interpret 01010010 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01010010 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 82.
  6. Add those contributions: 0 + 82 = 82.
  7. As an unsigned pattern, the same eight bits represent 82.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10101101; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10101110.
  11. Answer: signed(01010010) = 82.

Final answer: 82

Foundations · Problem 0084

Interpret 01010011 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01010011 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 83.
  6. Add those contributions: 0 + 83 = 83.
  7. As an unsigned pattern, the same eight bits represent 83.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10101100; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10101101.
  11. Answer: signed(01010011) = 83.

Final answer: 83

Foundations · Problem 0085

Interpret 01010100 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01010100 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 84.
  6. Add those contributions: 0 + 84 = 84.
  7. As an unsigned pattern, the same eight bits represent 84.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10101011; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10101100.
  11. Answer: signed(01010100) = 84.

Final answer: 84

Foundations · Problem 0086

Interpret 01010101 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01010101 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 85.
  6. Add those contributions: 0 + 85 = 85.
  7. As an unsigned pattern, the same eight bits represent 85.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10101010; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10101011.
  11. Answer: signed(01010101) = 85.

Final answer: 85

Foundations · Problem 0087

Interpret 01010110 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01010110 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 86.
  6. Add those contributions: 0 + 86 = 86.
  7. As an unsigned pattern, the same eight bits represent 86.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10101001; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10101010.
  11. Answer: signed(01010110) = 86.

Final answer: 86

Foundations · Problem 0088

Interpret 01010111 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01010111 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 87.
  6. Add those contributions: 0 + 87 = 87.
  7. As an unsigned pattern, the same eight bits represent 87.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10101000; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10101001.
  11. Answer: signed(01010111) = 87.

Final answer: 87

Foundations · Problem 0089

Interpret 01011000 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01011000 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 88.
  6. Add those contributions: 0 + 88 = 88.
  7. As an unsigned pattern, the same eight bits represent 88.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10100111; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10101000.
  11. Answer: signed(01011000) = 88.

Final answer: 88

Foundations · Problem 0090

Interpret 01011001 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01011001 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 89.
  6. Add those contributions: 0 + 89 = 89.
  7. As an unsigned pattern, the same eight bits represent 89.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10100110; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10100111.
  11. Answer: signed(01011001) = 89.

Final answer: 89

Foundations · Problem 0091

Interpret 01011010 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01011010 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 90.
  6. Add those contributions: 0 + 90 = 90.
  7. As an unsigned pattern, the same eight bits represent 90.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10100101; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10100110.
  11. Answer: signed(01011010) = 90.

Final answer: 90

Foundations · Problem 0092

Interpret 01011011 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01011011 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 91.
  6. Add those contributions: 0 + 91 = 91.
  7. As an unsigned pattern, the same eight bits represent 91.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10100100; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10100101.
  11. Answer: signed(01011011) = 91.

Final answer: 91

Foundations · Problem 0093

Interpret 01011100 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01011100 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 92.
  6. Add those contributions: 0 + 92 = 92.
  7. As an unsigned pattern, the same eight bits represent 92.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10100011; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10100100.
  11. Answer: signed(01011100) = 92.

Final answer: 92

Foundations · Problem 0094

Interpret 01011101 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01011101 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 93.
  6. Add those contributions: 0 + 93 = 93.
  7. As an unsigned pattern, the same eight bits represent 93.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10100010; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10100011.
  11. Answer: signed(01011101) = 93.

Final answer: 93

Foundations · Problem 0095

Interpret 01011110 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01011110 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 94.
  6. Add those contributions: 0 + 94 = 94.
  7. As an unsigned pattern, the same eight bits represent 94.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10100001; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10100010.
  11. Answer: signed(01011110) = 94.

Final answer: 94

Foundations · Problem 0096

Interpret 01011111 as an 8-bit two’s complement value.

Try it on paper first. The worked answer is hidden below.

Reveal detailed solution →
  1. Treat 01011111 as exactly eight bits.
  2. For signed 8-bit values the leftmost column has weight −128, not +128.
  3. The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
  4. The leading sign bit is 0, so its signed contribution is 0.
  5. The lower seven bits contribute 95.
  6. Add those contributions: 0 + 95 = 95.
  7. As an unsigned pattern, the same eight bits represent 95.
  8. The signed range for eight bits is −128 through +127.
  9. Bitwise inversion alone yields 10100000; inversion plus one wraps modulo 256.
  10. The eight-bit negated pattern is 10100001.
  11. Answer: signed(01011111) = 95.

Final answer: 95