1. **Problem 2.1.1:** Convert B7 (hex) and A16 (hex) to binary, perform two's complement subtraction, then convert the result to octal. 2. Convert B7 (hex) to binary: B = 1011, 7 = 0111, so B7 = 10110111. 3. Convert A16 (hex) to binary: A = 1010, 1 = 0001, 6 = 0110, so A16 = 101000010110. 4. Since B7 is 8 bits and A16 is 12 bits, pad B7 with leading zeros to 12 bits: 000010110111. 5. To subtract A16 from B7 using two's complement, find two's complement of A16: - Invert bits of A16: 010111101001 - Add 1: 010111101010 6. Add B7 and two's complement of A16: 000010110111 + 010111101010 = 011010100001 (ignore overflow) 7. Convert result 011010100001 to octal: Group bits in 3s from right: 011 010 100 001 Octal digits: 3 2 4 1 Final octal: 3241 --- 8. **Problem 2.1.2:** Multiply 213 (octal) and 4510 (decimal) by A,B (hex), then convert final answer to hexadecimal. 9. Convert 213 (octal) to decimal: $2\times8^2 + 1\times8^1 + 3\times8^0 = 128 + 8 + 3 = 139$. 10. 4510 is decimal 4510. 11. Convert A,B (hex) to decimal: A=10, B=11, so AB (hex) = $10\times16 + 11 = 171$. 12. Multiply 139 and 4510: $139 \times 4510 = 626,890$. 13. Multiply result by 171: $626,890 \times 171 = 107,163,190$. 14. Convert 107,163,190 to hexadecimal: Divide by 16 repeatedly or use calculator: Hexadecimal = 664B3AE --- 15. **Problem 2.1.3:** Divide 745 (octal) by 4, 2510 (decimal), convert final answer to decimal. 16. Convert 745 (octal) to decimal: $7\times8^2 + 4\times8^1 + 5\times8^0 = 448 + 32 + 5 = 485$. 17. Convert 4,2510 to decimal: 4,2510 means 4 and 2510, likely a typo; assuming 4 and 2510 separately. 18. Divide 485 by 4: $485 \div 4 = 121.25$. 19. Divide 121.25 by 2510: $121.25 \div 2510 \approx 0.0483$. 20. Final answer in decimal is approximately 0.0483. --- 21. **Problem 2.2:** ASCII stands for American Standard Code for Information Interchange. --- 22. **Problem 2.3:** Encode characters S, P, a, R, ? in ASCII: - S: 83 (decimal) = 01010011 (binary) - P: 80 (decimal) = 01010000 (binary) - a: 97 (decimal) = 01100001 (binary) - R: 82 (decimal) = 01010010 (binary) - ?: 63 (decimal) = 00111111 (binary) --- **Final answers:** - 2.1.1 result in octal: 3241 - 2.1.2 result in hex: 664B3AE - 2.1.3 result in decimal: approx 0.0483 - 2.2 ASCII meaning: American Standard Code for Information Interchange - 2.3 ASCII codes: S=83, P=80, a=97, R=82, ?=63