Master the Pearson Edexcel International GCSE (9-1) Computer Science exam with this examiner-backed guide. Learn how to avoid common pitfalls in binary shifts, network comparisons, flowchart design, and practical programming questions to secure top marks.
読了時間 3 分更新日: 2026年6月21日
試験の概要
試験数
2
満点
160
制限時間
5時間
出題形式
3
試験
時間
配点
問題数
配点比率
出題形式
Paper 1: Principles of Computer Science
2時間
80
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—
—
Paper 2: Application of Computational Thinking
3時間
80
—
—
—
評価段階
987654321U
電卓の規定
A scientific or graphical calculator is permitted. Graphical calculators must be in exam mode with all stored programs and data cleared before the exam; the calculator must not be able to retrieve stored text or formulae.
AO1: Demonstrate knowledge and understanding of the key concepts and principles of computer science. (37.5%)
AO2: Apply knowledge, understanding and skills to solve problems, design systems and write/refine algorithms. (47.5%)
AO3: Analyze and evaluate computer science systems, make judgements and present reasoned conclusions. (15%)
過去問と採点基準にもとづいて作成（2023–2025）。
電卓プログラム
Table mode for roots & turning points
Scientific calculator (e.g. Casio fx-991 series)
目的: Tabulate \(y\) across a range of \(x\) to locate sign changes (roots) and approximate maxima/minima.
使う場面: Solving or sketching a function when you want to find where its graph crosses or turns.
手順
Enter the function in TABLE mode, set the start, end and step, then read where the sign of \(y\) changes or where it peaks.
試験での注意: Allowed, but clear stored programs/data (graphical calculators in exam mode) and show the required working — unsupported calculator answers score no method marks.
Statistics mode (mean, SD & regression)
Scientific calculator (e.g. Casio fx-991 series)
目的: Read the mean \(\bar{x}\) and standard deviation directly, and the gradient/intercept (and \(r\)) of a linear regression for bivariate data.
使う場面: Any data-handling, statistics, or required-practical analysis question.
手順
Enter the data in STAT mode (1-VAR or A+BX), then recall \(\bar{x}\), \(\sigma\) or the regression coefficients.
試験での注意: Allowed, but clear stored programs/data (graphical calculators in exam mode) and show the required working — unsupported calculator answers score no method marks.
Carry exact values with Ans & memory
Scientific calculator (e.g. Casio fx-991 series)
目的: Keep full-precision intermediate values to avoid rounding errors.
使う場面: Multi-step calculations where premature rounding loses the final accuracy mark.
手順
Use Ans, STO/RCL or the M+ memory to reuse the unrounded result of each step; round only the final answer.
試験での注意: Allowed, but clear stored programs/data (graphical calculators in exam mode) and show the required working — unsupported calculator answers score no method marks.
Equation solver — to CHECK your working
Scientific calculator (e.g. Casio fx-991 series)
目的: Use the built-in EQN/SOLVE mode to verify roots of quadratics or simultaneous equations you have already solved by algebra.
使う場面: As a check only, after solving by hand.
手順
Enter the coefficients in EQN mode (or use SOLVE) and confirm they match your worked solution.
試験での注意: Allowed, but clear stored programs/data (graphical calculators in exam mode) and show the required working — unsupported calculator answers score no method marks.
よくあるミス
1high影響する配点: 2Networks
Stating both poles of a relative parameter as two distinct differences in network questions (e.g. 'WAN has higher latency' and 'LAN has lower latency').
回避方法: Compare two completely different characteristics (e.g. latency for one mark, and geographical coverage or ownership for the second mark).
2medium影響する配点: 1Binary
Failing to retain the sign bit when implementing arithmetic right shifts, or incorrectly padding the left side.
回避方法: In Two's Complement representation, when executing an arithmetic right shift, always copy the most significant bit (the sign bit) into the newly vacated bit positions on the left.
3high影響する配点: 1Algorithms
Omitting direction indicators/arrows on the lines connecting process blocks in flowchart diagrams.
回避方法: Ensure every line connecting shapes in a flowchart has a clearly visible arrowhead to explicitly demonstrate the sequence flow of the algorithm.
4medium影響する配点: 2Data types and structures
Hardcoding array offsets (e.g., substituting index 10 directly for structural replacements) instead of dynamically checking boundaries.
回避方法: Use dynamic boundary boundaries, such as len(array) or array.Length, and programmatically locate terminal empty elements using loops rather than fixed indices.
5medium影響する配点: 1Input/output
Failing to close open file handles at the end of output text file streams.
回避方法: Always invoke the .Close() method (e.g. writer.Close() in C# or file.close() in Python) to release OS file locks and secure data writing.
6medium影響する配点: 3Data storage and compression
Describing optical storage mechanics (lasers, lands, and pits) when asked to describe how data is read from magnetic platters.
回避方法: For magnetic storage, detail how platters spin, read/write heads detect changes in magnetic polarity, and how polarities translate to binary 1s and 0s.
7high影響する配点: 2Algorithms
Updating all columns simultaneously on every row of the trace table, rather than only changing values on a new row when states alter.
回避方法: Only record a value in a trace table on a new line when that specific variable's state has changed. Leave other cells in that row blank until they are modified.