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Unexpected Ordering

Age 5 to 7
Challenge Level Yellow star
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Prabhnoor from Willowbank School in New Zealand wrote:

The first time she dealt the cards out there was one card left the second time there were no cards left.

Lucia added:

I tried the trick and I figured that firstly, I had 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 and then I flipped it over just like the video did and ten was at the back. So then I flipped ten with nine so the ten was on the ground and nine on top. Then I flipped the eight and seven around so that eight was nearest to the ground and seven on top . I repeated this pattern so that I could get 1 on top of 2, 2 on top of 3, 3 on top of 4, and etc. That is why I would have the numbers backwards when I look at the cards/numbers.


Israel from Lark Rise Academy wrote:

Because when you collect the cards up, the bigger ones end up on the smaller ones so if you swap them around it would make it in order so that is how that trick is made.

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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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