4860 /www/nrich/html/content/id/4860/ 1 2011-02-01T00:00:01 <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"><p><a href="https://nrich.maths.org/8045">First Forward Into Logo</a><br></br> <strong>Previous:</strong> <a href="http://nrich.maths.org/public/viewer.php?obj_id=1542&amp;part=">FF10</a></p> <p> </p> <table style="" border=""> <tbody> <tr> <td>Consider the following procedure which uses two variables: <div>(Warning - you may have to press HALT to stop this procedure.)</div> <div>TO LOP :X :Y</div> <div>PR :X</div> <div>WAIT 120</div> <div>LOP :Y :X + :Y</div> <div>END</div> <br></br> <div>What do you think is happening this time?</div> <div>Try &#39;chasing&#39; through the procedure the values: x = 1 and y = 1.</div> <div>No longer surprised!</div> <div>Why do you think it goes on and on...?</div> <div>Yes it keeps starting itself again, but with different variables,</div> <div>moving on in the sequence by adding the last two variables.</div> <br></br> <div>Why not experiment further changing the fourth line?</div> <div>For example:</div> <div>LOP :Y :X +:Y*2</div> <div>LOP :Y :X - :Y*2</div> <div>LOP :Y :X * 2</div> <br></br> <div>Any surprises?</div> <br></br> <div>LOP :Y * 2 :X + :Y</div> <br></br> <div>Etc. Etc. Etc....</div> <br></br> <br></br> <div> </div> </td> <td> <div style="text-align: right;">1</div> <div style="text-align: right;">1</div> <div style="text-align: right;">3</div> <div style="text-align: right;">5</div> <div style="text-align: right;">11</div> <div style="text-align: right;">21</div> <div style="text-align: right;">43</div> <div style="text-align: right;">85</div> <div style="text-align: right;">171</div> <div style="text-align: right;">341</div> <div style="text-align: right;">683</div> <div style="text-align: right;">1365</div> <div style="text-align: right;">2731</div> <div style="text-align: right;">5461</div> <div style="text-align: right;">10923</div> <div style="text-align: right;">21845</div> <div style="text-align: right;">43691</div> <div style="text-align: right;">87381</div> <div style="text-align: right;">174763</div> <div style="text-align: right;">349525</div> <div style="text-align: right;">699051</div> <div style="text-align: right;">1398101</div> <div style="text-align: right;">2796203</div> <div style="text-align: right;">5592405</div> <div style="text-align: right;">11184811</div> <div style="text-align: right;">22369621</div> <div style="text-align: right;">44739243</div> <div style="text-align: right;">89478485</div> <div style="text-align: right;">178956971</div> <div style="text-align: right;">357913941</div> </td> </tr> </tbody> </table> <p> </p> <p><strong>Next:</strong><a href="http://nrich.maths.org/public/viewer.php?obj_id=4861&amp;part="> FF12</a><br></br>  </p></mdoxml> 2 3 0 0 1 1 1 This part introduces the use of Logo for number work. Learn how to use Logo to generate sequences of numbers. Information and Communications Technology Logo Sequences, Functions and Graphs Fibonacci sequence Using, Applying and Reasoning about Mathematics Practical Activity