Teaching article
An ordered card set permits a different search strategy
Use an ordered card set to explain why ordering changes available strategies.
Finding a middle value can rule out one side only when the order is known. Compare that inference with a sequential search, making the useful assumption visible before trying the same reasoning on shuffled cards.
Search sequentially. Try narrowing the ordered range. Compare checks.
Order is what justifies elimination
Demonstrate the ordering assumption explicitly. Excluding half a shuffled set after one comparison would not be justified by the selected value.
Checking a middle value can exclude one side only when order is known.
Do not apply that inference to shuffled cards.
What assumption supports elimination? Use eight cards.
Resources
- Human Robot Commands – Coding Without Screens Printable Game — Check the command conventions before using the sequence or debugging task.
Further reading
- CS Unplugged — Kidbots and algorithm activities
- Australian Curriculum Version 9 — Technologies overview
Read next
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- Two correct routes can be compared by different criteria
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