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false
AND needs both conditions true.
Class 9 · English Version · ICT
Data, logic and algorithms
Represent data, logic and an algorithm precisely enough to test.
Shared cross-level core and stretch unit. Start with the core questions, then use the stretch example for deeper work. The same unit is available in related class and board pathways; it is not a full grade-specific or examination-specification course. A teacher should select the appropriate depth and further topics.
Learn the idea
Data types influence allowed operations. A Boolean has two truth values. Conditions combine with AND, OR and NOT; brackets make the intended order explicit. An algorithm is a finite sequence of steps with clear inputs, decisions and outputs. Trace tables reveal whether the steps match the requirement.
Worked example
Rule: allow entry if guardian consent AND learner enrolled. True AND false is false. For a counter starting at 0 and adding 2 three times, the outputs are 2, 4 and 6.
- State the input type and allowed range.
- Translate the rule into conditions.
- Trace values for different cases.
Stretch example
A binary search repeatedly halves a sorted search range. Its prerequisite is sorted data with a suitable comparison. On an unsorted list, fewer steps do not make its answer valid.
Your written practice
Show your working on paper and enter your answer here. If it does not match, compare the model and try again.
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true
OR needs at least one condition true.
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8
1 → 2 → 4 → 8.
Write in your own words. A guardian or teacher should review this response.
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A program may concatenate text but add numbers; conversion rules depend on the language.
Distinguish representation from numeric value.
Write in your own words. A guardian or teacher should review this response.
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Test 7, 8 and 9: reject 7 and accept 8 and 9 under that rule.
Include the boundary itself and neighbours.
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5
32 → 16 → 8 → 4 → 2 → 1.
Write in your own words. A guardian or teacher should review this response.
Show model answer and explanation
Its assumptions about comparisons or operations may not hold, so validation or conversion is needed.
Identify an assumption and a response.
Rule and trace
Write pseudocode for a fictional borrowing limit and trace four cases.
Review with a guardian or teacher
- Define inputs.
- Include an invalid and a boundary case.
- Compare outputs with an independent rule.
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