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The Fire-fighter's Car Keys

Age 14 to 16
Challenge Level Yellow starYellow star
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See the Hint section for detailed support for students, but the main aims of this problem are :

1. If a calculation approach is adopted, to see the value of using a spreadsheet . Thinking through the calculation required and the spreadsheet commands (formulae) necessary to achieve that are prime Stage 4 activities.

2. To account for the general result that emerges, in such a way that the 'solution' then becomes obvious, adds an additional visualisation to the student's repertoire of possibilities.



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The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice.

NRICH is part of the family of activities in the Millennium Mathematics Project.

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