Computational Thinking | Edexcel GCSE Computer Science (1CP2)
Computational Thinking
- 107 questions
- 6 subtopics
- Paper 1
- Paper 1
Computational Thinking is examined in Paper 1, Principles of Computer Science.
It covers decomposition, abstraction and subprograms, algorithms, flowcharts and pseudocode, operators and trace tables, logic errors, test data and efficiency, searching and sorting algorithms and truth tables.
Sample questions from Computational Thinking
Answer each one closed book first, then open the answer.
-
Decomposition, abstraction and subprograms
A program models a game of noughts and crosses. Which details of a real game would abstraction remove?
Show the answer
Abstraction would remove the pen, the paper and the players’ appearance. The model keeps only the 3 × 3 grid, the marks and whose turn it is. -
Decomposition, abstraction and subprograms
Why does using subprograms save a programmer time?
Show the answer
A subprogram is written once and can be called as many times as needed. The same code does not have to be repeated in several places. -
Algorithms, flowcharts and pseudocode
What is the difference between count-controlled and condition-controlled repetition?
Show the answer
Count-controlled repetition runs a fixed number of times, known before the loop starts. Condition-controlled repetition keeps going while a condition holds, so the number of repeats may be unknown. -
Algorithms, flowcharts and pseudocode
Why is a string treated as a data structure?
Show the answer
A string is a sequence of characters, each with its own index. Single characters can be reached in the same way as items in an array. -
Operators and trace tables
What is the value of 7 + 3 × 2, and why?
Show the answer
The value is 13. Multiplication is carried out before addition, so 3 × 2 = 6 is worked out first. -
Operators and trace tables
Describe a trace table.
Show the answer
A trace table is a grid with a column for each variable and one for the output. Each row records the values as the algorithm runs, step by step. -
Logic errors, test data and efficiency
An algorithm finds the mean of five marks by adding them up and dividing by 4. What type of error is this, and how is it corrected?
Show the answer
The fault is a logic error, because the algorithm runs but gives a wrong mean. The total should be divided by 5. -
Logic errors, test data and efficiency
Why is the number of compares used to judge an algorithm’s efficiency?
Show the answer
Each comparison takes processing time. An algorithm that reaches the same result with fewer compares is more efficient.
The 6 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| Decomposition, abstraction and subprograms | Decomposition and abstraction with worked examples from maps, games and school reports, and how subprograms save time, simplify testing and maintenance, and can be reused. | 16 |
| Algorithms, flowcharts and pseudocode | Algorithms and informal pseudocode, the six flowchart symbols, sequence, selection, repetition and iteration, input, processing and output, variables, constants, arrays and records. | 24 |
| Operators and trace tables | Modulus, integer division and exponentiation with worked values, the order of operations, relational and logical operators in conditions, and trace tables for short algorithms. | 16 |
| Logic errors, test data and efficiency | Syntax, logic and runtime errors, finding and fixing logic errors in algorithms, normal, boundary and erroneous test data, and judging efficiency by compares, passes and memory. | 17 |
| Searching and sorting algorithms | Linear and binary searches traced through short lists, worst-case compares, and bubble and merge sorts worked step by step, with when each is the better choice. | 18 |
| Truth tables | AND, OR and NOT, truth tables with up to three inputs, worked values of combined expressions, and alarm and heating problems solved with logic. | 16 |
How the guide is worked
Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.
-
Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
-
Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
-
Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.
Read the full method, the return schedule and the research behind it.
Nearby topics
Edexcel GCSE Computer Science Active Recall Guide
Every topic, not just this one. 680 questions with their answers.