Year 13 CIE Computer Science Unit Test Mock Paper Analysis | Year 13 CIE 计算机 单元测试模拟卷解析

📚 Year 13 CIE Computer Science Unit Test Mock Paper Analysis | Year 13 CIE 计算机 单元测试模拟卷解析

This article provides a detailed walkthrough of a mock unit test designed for Year 13 CIE Computer Science students. Each question targets key syllabus areas, and we offer step-by-step solutions and explanations to strengthen your exam technique.

本文对为Year 13 CIE计算机科学学生设计的一套单元测试模拟卷进行了详细解析。每道题目针对关键考纲领域，我们提供逐步的解决方案和解释，以强化你的考试技巧。

1. Number Systems and Data Representation | 数制与数据表示题目解析

Question: Convert the denary number 86 into its 8‑bit binary and hexadecimal equivalents. Then, using 8‑bit two’s complement, represent –86. State the range of signed integers possible in 8‑bit two’s complement.

题目：将十进制数86转换为8位二进制和十六进制。然后用8位二进制补码表示–86。并说明8位二进制补码能表示的有符号整数范围。

Answer: To convert 86 to binary, repeatedly divide by 2: 86 ÷ 2 = 43 rem 0; 43 ÷ 2 = 21 rem 1; 21 ÷ 2 = 10 rem 1; 10 ÷ 2 = 5 rem 0; 5 ÷ 2 = 2 rem 1; 2 ÷ 2 = 1 rem 0; 1 ÷ 2 = 0 rem 1. Reading remainders upwards gives 1010110. For 8 bits, pad with a leading zero: 01010110. In hexadecimal, split into nibbles: 0101 (5) and 0110 (6), so 0x56.

解析：将86连续除以2取余数，自底向上读取得到1010110。作为8位二进制数写作01010110。十六进制按4位分组：0101为5，0110为6，因此是56₁₆。

For –86 in two’s complement: start with +86 = 01010110. Flip all bits → 10101001. Add 1 → 10101010. Thus –86 is 10101010. The range for signed 8‑bit two’s complement is –2⁷ to 2⁷–1, i.e. –128 to 127.

对于–86的补码：从+86的二进制01010110开始，按位取反得10101001，再加1得10101010。因此–86表示为10101010。8位二进制补码的表示范围是–2⁷ 到 2⁷–1，即 –128 至 127。

2. Boolean Algebra and Logic Gates | 布尔代数与逻辑门题目解析

Question: Simplify the Boolean expression F = ¬(A ∧ B) ∨ ¬(¬A ∨ B). Draw the logic circuit for the

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