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  <resource>
  <id>7473</id>
  <path>/www/nrich/html/content/id/7473/</path>
  <resourceTypeID>1</resourceTypeID>
  <last_published>2011-07-23T10:10:45</last_published>
  <indexXML>&lt;mdoxml version=&quot;1.0&quot;&gt;&lt;br&gt;&lt;/br&gt;
&lt;p&gt;&lt;em&gt;This activity has been particularly created for the most able. (The pupils that you come across in many classrooms just once every few years.)&lt;/em&gt;&lt;/p&gt;
&lt;p&gt;This activity also follow on for those who have successfully worked at &lt;a href=&quot;http://nrich.maths.org/66&amp;amp;part=&quot;&gt;Doplication.&lt;/a&gt; &lt;br&gt;&lt;/br&gt;
 &lt;br&gt;&lt;/br&gt;
Let me help you visualise this representation of a 3D situation.&lt;br&gt;&lt;/br&gt;
It's kind of two set of three adjacent cubes with balls at each vertex.&lt;br&gt;&lt;/br&gt;
Towards the bottom left of the picture are the eight large balls, then going backwards there are eight medium red balls and further back are eight small ones.&lt;br&gt;&lt;/br&gt;
In the centre of the front three cubes are three orange balls and at the centre of the rear cubes are three brown ones.&lt;/p&gt;
&lt;div style=&quot;text-align: center;&quot;&gt; &lt;/div&gt;
&lt;div style=&quot;text-align: center;&quot;&gt; &lt;mdo:image width=&quot;401&quot; height=&quot;163&quot; src=&quot;new6cubes.jpg&quot; alt=&quot;new6&quot;&gt;&lt;/mdo:image&gt;&lt;/div&gt;
&lt;div style=&quot;text-align: left;&quot;&gt;In Doplication you would have had;&lt;/div&gt;
&lt;div style=&quot;text-align: center;&quot;&gt; &lt;/div&gt;
&lt;div style=&quot;text-align: center;&quot;&gt; &lt;mdo:image width=&quot;249&quot; height=&quot;175&quot; src=&quot;Axitate%20version%204%3F3.jpg&quot; alt=&quot;axitate version&quot;&gt;&lt;/mdo:image&gt;&lt;/div&gt;
&lt;div style=&quot;text-align: left;&quot;&gt;which we called $4$ ? $3$.&lt;/div&gt;
&lt;div style=&quot;text-align: left;&quot;&gt;In this activity it would be called something different involving $4, 3, 2$. Just for now I am going to use @, so the diagram above represents $4$@$3$@$2$.&lt;/div&gt;
&lt;div style=&quot;text-align: left;&quot;&gt;I invite you to explore many such arrangements and find a way of recording your results.&lt;/div&gt;
&lt;div style=&quot;text-align: left;&quot;&gt;You might like to just look at the arrangements that are like cubes - $3$@$3$@$3$ , $4$@$4$@$4$, $5$@$5$@$5$, etc.&lt;/div&gt;
&lt;div style=&quot;text-align: left;&quot;&gt; &lt;/div&gt;
&lt;div style=&quot;text-align: left;&quot;&gt;As with most mathematics it's good to compare so maybe compare the results for squares in Doplication and cubes in 3D Stacks.&lt;/div&gt;
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&lt;h3&gt;&lt;span style=&quot;font-weight: bold;&quot;&gt;Why do this
problem?&lt;/span&gt;&lt;/h3&gt;

&lt;div&gt;This &lt;a href=&quot;http://nrich.maths.org/7473&amp;amp;part=&quot;&gt;activity&lt;/a&gt; is
specially designed for the highest-attaining pupils that you ever
come across. It acts as a further extension to  &lt;a href=&quot;http://nrich.maths.org/66&amp;amp;part=&quot;&gt;Doplication&lt;/a&gt;. It's an
activity that is intended to give opportunities for those pupils to
explore deeply using their intuition and flair in the areas of both
spatial awareness and number replationships and
patterns. &lt;/div&gt;

&lt;br&gt;&lt;/br&gt;
 

&lt;h3&gt;Possible approach&lt;/h3&gt;

&lt;div&gt;As this is designed for the highest attaining, it might be
presented as on the website or in a one-to-one situation,
encouraging discussion between adult and pupil.  The pupils
may need access to a spreadsheet once many number results are being
acquired.&lt;/div&gt;

&lt;br&gt;&lt;/br&gt;
 

&lt;h3&gt;Key questions&lt;/h3&gt;

&lt;div&gt;Tell me about what you have found.&lt;/div&gt;

&lt;div&gt;Can you describe the ways that you arrived at these
numbers?&lt;/div&gt;

&lt;div&gt;How did you construct this on the spreadsheet you used?&lt;/div&gt;

&lt;br&gt;&lt;/br&gt;
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If its useful for the teacher here are some little bits.&lt;br&gt;&lt;/br&gt;
&lt;mdo:image width=&quot;595&quot; height=&quot;52&quot; src=&quot;some%20cube%20results.jpg&quot; alt=&quot;cube results&quot;&gt;&lt;/mdo:image&gt;&lt;br&gt;&lt;/br&gt;
Some more for the cube ones.&lt;br&gt;&lt;/br&gt;
 &lt;mdo:image width=&quot;711&quot; height=&quot;347&quot; src=&quot;extra%20resulst.jpg&quot; alt=&quot;extras&quot;&gt;&lt;/mdo:image&gt;&lt;br&gt;&lt;/br&gt;
 &lt;br&gt;&lt;/br&gt;
For results from $3$ to $7$ some layers to show the answers&lt;br&gt;&lt;/br&gt;
 &lt;br&gt;&lt;/br&gt;
 &lt;mdo:image width=&quot;542&quot; height=&quot;407&quot; alt=&quot;general&quot; src=&quot;some%20general%20results.jpg&quot;&gt;&lt;/mdo:image&gt;&lt;br&gt;&lt;/br&gt;
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  <end_user_role>5</end_user_role>
  <difficulty>5</difficulty>
  <keystage1>0</keystage1>
  <keystage2>1</keystage2>
  <keystage3>1</keystage3>
  <keystage4>0</keystage4>
  <keystage4plus>0</keystage4plus>
  <title>3D Stacks</title>
  <description>
Can you find a way of representing these arrangements of balls?

</description>
  <spec_group>Using, Applying and Reasoning about Mathematics
    <specifier>Representing</specifier>
  </spec_group>
  <spec_group>Using, Applying and Reasoning about Mathematics
    <specifier>Visualising</specifier>
  </spec_group>
</resource>