Flabbergasted

What is the longest sequence you can make from the numbers below?

123456
789101112
131415161718
192021222324

Each number in the sequence must be a factor or multiple of the previous number.

 

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Topics: Starter | Arithmetic | Factors | Mental Methods | Number

  • Transum,
  •  
  • This is a fascinating activity on a number of levels. It is accessible to pupils who have learned about factors and multiples and need practice but it also proves to be an interesting activity for older pupils who may analyse the situation from a more general perspective. Finding the best solution and being sure that it can't be bettered is a challenge for the most able. What strategies did your class come up with?
  • Mrs M,
  •  
  • Good to revise factors and multiples.
  • WKGS, Wirral
  •  
  • We got 18!
  • Paula, Portsmoiuth
  •  
  • I got 20!
  • Katy, Sydney
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  • Got 21! Definitely going to this to extend my students.
  • Room 5, Cool School
  •  
  • WE got 21 too!! Took us afew goes but we think 21 is brilliant.
  • Mr S, Haslemere
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  • We got 20, please post solution for 21.
  • Kai and Finn, 5M
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  • Finn and I got 20. WOW!
  • Luca, Canberra, Australia
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  • I got 20 but still working on it.
  • Oliver, Tenterden Joinior
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  • Amazing I got the best score in my class 15.
  • Miss Collins,
  •  
  • This a really great starter for my class. It makes you think a lot.
  • Miss McElderry WMS, Twitter
  •  
  • ImagineMath,
  •  
  • Here's a solution for 21:
    {23, 1, 11, 22, 2, 14, 7, 21, 3, 9, 18, 6, 12, 24, 8, 16, 4, 20, 10, 5, 15}.
  • 9M4, Pudsey
  •  
  • 9M4 found 21 steps...had to start with a prime number nice challenge.

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Note to teacher: Doing this activity once with a class helps students develop strategies. It is only when they do this activity a second time that they will have the opportunity to practise those strategies. That is when the learning is consolidated. Click the button above to regenerate another version of this starter from random numbers.



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