Fully solved problem book
Signed eight-bit values
Set 6 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 0161
Interpret 10100000 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10100000 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 32.
- Add those contributions: -128 + 32 = -96.
- As an unsigned pattern, the same eight bits represent 160.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01011111; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01100000.
- Answer: signed(10100000) = -96.
Final answer: -96
Foundations · Problem 0162
Interpret 10100001 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10100001 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 33.
- Add those contributions: -128 + 33 = -95.
- As an unsigned pattern, the same eight bits represent 161.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01011110; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01011111.
- Answer: signed(10100001) = -95.
Final answer: -95
Foundations · Problem 0163
Interpret 10100010 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10100010 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 34.
- Add those contributions: -128 + 34 = -94.
- As an unsigned pattern, the same eight bits represent 162.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01011101; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01011110.
- Answer: signed(10100010) = -94.
Final answer: -94
Foundations · Problem 0164
Interpret 10100011 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10100011 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 35.
- Add those contributions: -128 + 35 = -93.
- As an unsigned pattern, the same eight bits represent 163.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01011100; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01011101.
- Answer: signed(10100011) = -93.
Final answer: -93
Foundations · Problem 0165
Interpret 10100100 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10100100 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 36.
- Add those contributions: -128 + 36 = -92.
- As an unsigned pattern, the same eight bits represent 164.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01011011; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01011100.
- Answer: signed(10100100) = -92.
Final answer: -92
Foundations · Problem 0166
Interpret 10100101 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10100101 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 37.
- Add those contributions: -128 + 37 = -91.
- As an unsigned pattern, the same eight bits represent 165.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01011010; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01011011.
- Answer: signed(10100101) = -91.
Final answer: -91
Foundations · Problem 0167
Interpret 10100110 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10100110 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 38.
- Add those contributions: -128 + 38 = -90.
- As an unsigned pattern, the same eight bits represent 166.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01011001; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01011010.
- Answer: signed(10100110) = -90.
Final answer: -90
Foundations · Problem 0168
Interpret 10100111 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10100111 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 39.
- Add those contributions: -128 + 39 = -89.
- As an unsigned pattern, the same eight bits represent 167.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01011000; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01011001.
- Answer: signed(10100111) = -89.
Final answer: -89
Foundations · Problem 0169
Interpret 10101000 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10101000 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 40.
- Add those contributions: -128 + 40 = -88.
- As an unsigned pattern, the same eight bits represent 168.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01010111; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01011000.
- Answer: signed(10101000) = -88.
Final answer: -88
Foundations · Problem 0170
Interpret 10101001 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10101001 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 41.
- Add those contributions: -128 + 41 = -87.
- As an unsigned pattern, the same eight bits represent 169.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01010110; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01010111.
- Answer: signed(10101001) = -87.
Final answer: -87
Foundations · Problem 0171
Interpret 10101010 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10101010 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 42.
- Add those contributions: -128 + 42 = -86.
- As an unsigned pattern, the same eight bits represent 170.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01010101; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01010110.
- Answer: signed(10101010) = -86.
Final answer: -86
Foundations · Problem 0172
Interpret 10101011 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10101011 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 43.
- Add those contributions: -128 + 43 = -85.
- As an unsigned pattern, the same eight bits represent 171.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01010100; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01010101.
- Answer: signed(10101011) = -85.
Final answer: -85
Foundations · Problem 0173
Interpret 10101100 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10101100 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 44.
- Add those contributions: -128 + 44 = -84.
- As an unsigned pattern, the same eight bits represent 172.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01010011; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01010100.
- Answer: signed(10101100) = -84.
Final answer: -84
Foundations · Problem 0174
Interpret 10101101 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10101101 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 45.
- Add those contributions: -128 + 45 = -83.
- As an unsigned pattern, the same eight bits represent 173.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01010010; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01010011.
- Answer: signed(10101101) = -83.
Final answer: -83
Foundations · Problem 0175
Interpret 10101110 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10101110 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 46.
- Add those contributions: -128 + 46 = -82.
- As an unsigned pattern, the same eight bits represent 174.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01010001; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01010010.
- Answer: signed(10101110) = -82.
Final answer: -82
Foundations · Problem 0176
Interpret 10101111 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10101111 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 47.
- Add those contributions: -128 + 47 = -81.
- As an unsigned pattern, the same eight bits represent 175.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01010000; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01010001.
- Answer: signed(10101111) = -81.
Final answer: -81
Foundations · Problem 0177
Interpret 10110000 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10110000 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 48.
- Add those contributions: -128 + 48 = -80.
- As an unsigned pattern, the same eight bits represent 176.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01001111; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01010000.
- Answer: signed(10110000) = -80.
Final answer: -80
Foundations · Problem 0178
Interpret 10110001 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10110001 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 49.
- Add those contributions: -128 + 49 = -79.
- As an unsigned pattern, the same eight bits represent 177.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01001110; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01001111.
- Answer: signed(10110001) = -79.
Final answer: -79
Foundations · Problem 0179
Interpret 10110010 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10110010 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 50.
- Add those contributions: -128 + 50 = -78.
- As an unsigned pattern, the same eight bits represent 178.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01001101; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01001110.
- Answer: signed(10110010) = -78.
Final answer: -78
Foundations · Problem 0180
Interpret 10110011 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10110011 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 51.
- Add those contributions: -128 + 51 = -77.
- As an unsigned pattern, the same eight bits represent 179.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01001100; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01001101.
- Answer: signed(10110011) = -77.
Final answer: -77
Foundations · Problem 0181
Interpret 10110100 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10110100 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 52.
- Add those contributions: -128 + 52 = -76.
- As an unsigned pattern, the same eight bits represent 180.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01001011; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01001100.
- Answer: signed(10110100) = -76.
Final answer: -76
Foundations · Problem 0182
Interpret 10110101 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10110101 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 53.
- Add those contributions: -128 + 53 = -75.
- As an unsigned pattern, the same eight bits represent 181.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01001010; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01001011.
- Answer: signed(10110101) = -75.
Final answer: -75
Foundations · Problem 0183
Interpret 10110110 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10110110 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 54.
- Add those contributions: -128 + 54 = -74.
- As an unsigned pattern, the same eight bits represent 182.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01001001; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01001010.
- Answer: signed(10110110) = -74.
Final answer: -74
Foundations · Problem 0184
Interpret 10110111 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10110111 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 55.
- Add those contributions: -128 + 55 = -73.
- As an unsigned pattern, the same eight bits represent 183.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01001000; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01001001.
- Answer: signed(10110111) = -73.
Final answer: -73
Foundations · Problem 0185
Interpret 10111000 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10111000 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 56.
- Add those contributions: -128 + 56 = -72.
- As an unsigned pattern, the same eight bits represent 184.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01000111; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01001000.
- Answer: signed(10111000) = -72.
Final answer: -72
Foundations · Problem 0186
Interpret 10111001 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10111001 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 57.
- Add those contributions: -128 + 57 = -71.
- As an unsigned pattern, the same eight bits represent 185.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01000110; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01000111.
- Answer: signed(10111001) = -71.
Final answer: -71
Foundations · Problem 0187
Interpret 10111010 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10111010 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 58.
- Add those contributions: -128 + 58 = -70.
- As an unsigned pattern, the same eight bits represent 186.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01000101; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01000110.
- Answer: signed(10111010) = -70.
Final answer: -70
Foundations · Problem 0188
Interpret 10111011 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10111011 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 59.
- Add those contributions: -128 + 59 = -69.
- As an unsigned pattern, the same eight bits represent 187.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01000100; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01000101.
- Answer: signed(10111011) = -69.
Final answer: -69
Foundations · Problem 0189
Interpret 10111100 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10111100 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 60.
- Add those contributions: -128 + 60 = -68.
- As an unsigned pattern, the same eight bits represent 188.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01000011; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01000100.
- Answer: signed(10111100) = -68.
Final answer: -68
Foundations · Problem 0190
Interpret 10111101 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10111101 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 61.
- Add those contributions: -128 + 61 = -67.
- As an unsigned pattern, the same eight bits represent 189.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01000010; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01000011.
- Answer: signed(10111101) = -67.
Final answer: -67
Foundations · Problem 0191
Interpret 10111110 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10111110 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 62.
- Add those contributions: -128 + 62 = -66.
- As an unsigned pattern, the same eight bits represent 190.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01000001; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01000010.
- Answer: signed(10111110) = -66.
Final answer: -66
Foundations · Problem 0192
Interpret 10111111 as an 8-bit two’s complement value.
Try it on paper first. The worked answer is hidden below.
Reveal detailed solution →
- Treat 10111111 as exactly eight bits.
- For signed 8-bit values the leftmost column has weight −128, not +128.
- The remaining seven columns have weights 64, 32, 16, 8, 4, 2 and 1.
- The leading sign bit is 1, so its signed contribution is -128.
- The lower seven bits contribute 63.
- Add those contributions: -128 + 63 = -65.
- As an unsigned pattern, the same eight bits represent 191.
- The signed range for eight bits is −128 through +127.
- Bitwise inversion alone yields 01000000; inversion plus one wraps modulo 256.
- The eight-bit negated pattern is 01000001.
- Answer: signed(10111111) = -65.
Final answer: -65