lesson
Make requirements observable
1 · Learn
A requirement should describe behaviour that can be checked. 'Easy to use' needs concrete tasks and criteria; 'reject a score outside 0–100' gives a clear rule. Tests should be planned before declaring implementation complete.
Separate a requirement from an implementation preference. A user may need a saved result without caring which internal storage format is chosen.
2 · Worked example
For a score form, tests include -1,0,100,101 and a non-numeric entry. These check the stated range and type rules.
3 · Your turn
What expected result should a score of 101 have under the 0–100 rule?
Check your answer
It should be rejected with a clear correction message and not saved as valid.
4 · Apply your learning
Turn three vague wishes into testable requirements for a small local quiz project.
Adult guidance and safety
Work in an approved local sandbox with invented records and test accounts. Do not access other people's systems or collect real credentials. Practical project evidence is required in addition to these explanations; this is not a specified GCSE Computer Science course.
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Write, draw or show your working. Use a mouse, pen or finger. This pad is not a submitted answer.
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Open a picture saved on this device to draw on it again. Opening replaces the drawing, but Undo can restore it. PNG only, up to 4 MB and 4096 × 4096 pixels. The picture stays in this browser; it is not uploaded. Paper lines in a saved picture become part of that picture.
Clear the drawing? Your typed notes will stay. You can undo this action.
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Open a UTF-8 TXT file from this device, up to 40 KB and 10,000 characters. It stays in this browser. Opening can be undone until you type again. Downloads keep a new copy; they do not change the file you opened.
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Typed notes are not submitted answers.
Check a calculation · Year 5 onward
Use this only when your teacher or adult allows a calculator for the task. Show your thinking first. It does not replace mental or written arithmetic and does not mark your lesson answer.
Powers, roots and trigonometry · Year 7 onward
Use only when the task allows a calculator. Choose one operation at a time and record your working. Trigonometry here always uses degrees (DEG), not radians. Inverse sine, cosine and tangent return an angle, not a reciprocal. Keep exact fractions and π in answers when requested.
Approximate numerical results use up to 12 significant digits. Inverse sine returns −90° to 90°, inverse cosine 0° to 180°, and inverse tangent −90° to 90°; these are principal values, not every possible solution of a trigonometric equation.
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Interactive activity
Year 10 Computing learning routine
Practice activity. It does not change your saved quiz score.
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