Data types
Understanding and using integer, real, Boolean, character, and string data types.
Full topic guide: the detailed syllabus page with worked examples and common mistakes lives at studyvector.co.uk/gcse/computer-science/programming/variables-data-types.
Topic preview: Data types
Sample stems from the StudyVector question bank (AQA · Edexcel · OCR) — not generic filler text.
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Coverage and provenance
What this page is based on
StudyVector does not present unsupported question coverage as complete. Read how questions are selected and reviewed.
Topic explanation
Variables are named memory locations used to store data that can change while a program is running. Each variable has a data type, which tells the computer what kind of data it can hold, such as an integer (whole number), a float (decimal number), a string (text), or a Boolean (True/False). Using the correct data type is crucial for writing efficient and error-free code.
Data types is easiest to revise when it is treated as a precise exam behaviour, not a loose note-taking category. In GCSE Computer Science, the goal is to recognise how the topic appears in a question, identify the command word, and decide what evidence, method, or vocabulary earns marks. StudyVector keeps this page tied to AQA · Edexcel · OCR language where coverage is available, then routes practice towards the same topic so revision moves from explanation into retrieval.
A strong revision session starts with a short recall check. Write down the rule, definition, process, or method linked to Data types before looking at any notes. Then answer one exam-style prompt and compare your answer with the mark-scheme logic: did you make a clear point, support it with the right step, and avoid drifting into a nearby topic? This matters because many lost marks come from almost-correct answers that do not match the expected structure.
Use this guide as the first layer: understand the topic, look at the worked examples, complete the mini quiz, then move into full practice. The full StudyVector practice loop is designed to capture whether mistakes are caused by knowledge, method, language, or timing. That distinction is important. If the error is factual, you need reteaching. If the error is method-based, you need a worked retry. If the error is wording, you need command-word calibration. That is how Data types becomes a controlled revision target rather than another page in a folder.
Lost marks → repair task
Why marks are usually lost here
These are the error patterns StudyVector looks for after an attempt. The goal is not a generic explanation; it is one repair move and one follow-up question.
Command-word miss
Examiner move: Answer the action in the command word before adding extra detail.
Repair drill: 60-second rewrite: start the answer with explain, compare, evaluate, state, or calculate in mind.
Missing chain of reasoning
Examiner move: Show the link between point, method, evidence, and conclusion instead of jumping to the final line.
Repair drill: Write the missing because/therefore step, then retry one isomorphic question.
Weak evidence or data reference
Examiner move: Use a precise value, quote, example, diagram feature, or syllabus term to support the claim.
Repair drill: Add one concrete reference to the answer and remove any generic sentence that does not earn a mark.
Mini quiz
Use these checks before full practice. They test topic recognition, exam technique, and whether you can connect the explanation to a marked response.
1. What should you check first when a Data types question appears in GCSE Computer Science?
- A.The command word and the exact topic focus
- B.The longest paragraph in your notes
- C.A memorised answer from a different topic
2. Which revision action gives the strongest evidence that Data types is improving?
- A.Rereading the explanation twice
- B.Answering a timed exam-style question and reviewing lost marks
- C.Highlighting every key phrase in the topic notes
Sample questions
Topic-specific public question previews are still being reviewed. We keep them off public pages until the topic match is safe.
Exam tips
- Read the command word carefully — "explain" needs reasons; "state" expects a short fact.
- For Data types, show structured working even when you are practising multiple choice — it builds accuracy under time pressure.
- Mark yourself against the mark scheme style: one clear point per mark, in logical order.
- Come back to this topic after a day or two; short spaced reviews beat one long cram.
Worked examples
Example 1
Modelled exam response
In Python, to store a user's age: `userAge = 15`. Here, `userAge` is the variable name, and the value `15` is an integer. To store their name: `userName = "Alex"`. Here, `userName` is the variable, and `"Alex"` is a string. If we wanted to calculate their age next year, we could write `ageNextYear = userAge + 1`.
Example 2
Identify the task before answering
Question type: a Data types prompt asks for a clear response in GCSE Computer Science. Step 1: underline the command word. Step 2: name the exact part of Data types being tested. Step 3: decide whether the mark scheme wants a definition, method, explanation, comparison, or calculation. Why it works: most weak answers fail before the content starts because they answer the topic generally rather than the exact exam task.
Example 3
Turn feedback into a repair task
Suppose your answer shows partial understanding but loses marks for precision. First, rewrite the missing mark as a short target: "I need to state the mechanism, unit, reason, or evidence explicitly." Then answer one similar question without notes. Finally, compare the second attempt with the first and check whether the same mark was recovered. Why it works: Data types improves faster when feedback creates a specific retry, not another passive reading session.
Next revision routes from this subject
Good topic pages should lead naturally into the next useful page. Use these links to stay inside the same strand or jump into the next topic area without starting your search again.
Stay in the same topic area
Common mistakes
- Choosing the wrong data type, for example, storing a price like £9.99 as an integer instead of a float, which would lose the decimal part.
- Trying to perform operations on incompatible data types, like trying to mathematically add a string to a number without converting it first.
- Using unclear variable names like `x` or `temp`. Good variable names like `userAge` or `totalScore` make code much easier to read and understand.
Exam board notes
This is an absolute fundamental for all programming components of the AQA, Edexcel, and OCR specifications. You must know the common data types (Integer, Real/Float, String, Character, Boolean) and how to use them in the specified language.
FAQs
What is the difference between a variable and a constant?
A variable is a value that is expected to change during the program's execution. A constant is a value that, once assigned, should not be changed. Using constants for fixed values like the rate of VAT makes code more reliable.
What is casting in programming?
Casting is the process of converting a variable from one data type to another. For example, if you get a number as input from a user, it is often read as a string, so you need to cast it to an integer or float before you can use it in calculations.
More on StudyVector
Full practice set
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