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Special Numbers

My two digit number is special because adding the sum of its digits to the product of its digits gives me my original number. What could my number be?

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Your Number Is...

Think of a number... follow the machine's instructions. I know what your number is! Can you explain how I know?

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First Forward Into Logo 6: Variables and Procedures

Learn to write procedures and build them into Logo programs. Learn to use variables.

Your Number Was...

Stage: 3 Challenge Level: Challenge Level:1

Can you write each step of the machine's instructions as a function machine?
What happens if you work backwards?
 
 
Think of a number: ? add 3: ?+ 3 double: ?+? +6 add 4: ?+?+10 halve: ?+5 take away the number you started with: 5  
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. More information on many of our other activities can be found here.
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NRICH is part of the family of activities in the Millennium Mathematics Project.