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Fifteen Cards

Stage: 2 Challenge Level: Challenge Level:1


We have had 400 solutions sent in from all over the world. There were also a few solutions that unfortunately used either one number twice or used a number larger than 15.

I was pleased to hear from Max Bedgrove Junior; Callum and Zaki, Thomas and Zain (ABHS) who said:

We were very excited as this was the best thing we have ever done in Maths.  We worked as a team and managed to find the solutions.


Shikha sent in solutions from two groups at Korea International School (Pangyo) in South Korea.They are Philip, Eric and Seungji; and Konu, Anjani and Alice.  Both groups sent in videos using educreations, which I can recommend to you all:

https://www.educreations.com/lesson/view/math-card-challenge/24792192/?s=1iOetQ&ref=app
https://www.educreations.com/lesson/view/fifteen-cards/24792351/?s=doRqVH&ref=appemail



Also Mr M's Maths Group at Bearwood Primary School sent in their solutions plus some further observations:

We found two solutions to this problem.

We used trial and improvement to find solutions. Some of us didn't manage to find a solution, but we worked hard on changing the order of the cards.
Our two solutions were: 8, 7, 13, 10, 6, 12, 9 and 6, 9, 11, 12, 4, 14, 7

Oliver also spotted that the numbers in the third, fourth and the sixth positions were two digit numbers.

We also spotted that the sets of numbers in our solution have a difference of 2.

The totals of both lines have a difference of 2.

We also spotted a pattern in odd and even numbers in our solutions.

Zach at the end of the month sent in this document which is an excellent example of a way of working  Fifteen Cards Zach T.doc


A very big thank you for all the solutions that came in from different schools and a reminder to read the instructions carefully. Although of course you may decide to alter the rules and do an alternative investigation.