lesson
The condition must eventually change
1 · Learn
A while loop repeats while its condition is true. If the body never changes anything affecting the condition, the loop may never terminate. Plan the initial state, condition and update before running it.
For a model count starting at 0, repeatedly adding 1 while count < 3 gives updates to 1, 2 and 3, then stops. If count already begins at 3, the body runs zero times.
2 · Worked example
I trace count values before and after each iteration. This reveals whether the loop stops at the intended boundary and whether an update was accidentally omitted.
3 · Your turn
If count starts at 5 and the condition is count < 3, how many iterations run?
Check your answer
Zero; the condition is false before the first iteration.
4 · Apply your learning
Trace a terminating and a deliberately incomplete paper loop; identify the missing update without running an uncontrolled loop.
Adult guidance and safety
Use an approved private interpreter, simulator or authoring tool with fictional data. Trace and predict before running. Never execute unknown downloaded code, inspect real credentials or use other people's private data. Working examples still need saved-project and assessment integration before release.
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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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