7373 /www/nrich/html/content/id/7373/ 2 2011-06-14T12:16:39 <mdoxml version="1.0"><br></br> <p>Square matrices of the same dimension can be added, subtracted and multiplied. You can also convert a matrix into a scalar by taking the determinant. You can also multiply or divide a matrix by a scalar. Perfect for a game of matrix countdown!<br></br>  <br></br>  <mdo:flash height="250" width="550"><param name="allowfullscreen" value="true" ></param><param name="movie" value="/content/id/7373/countdown.swf" ></param><param name="flashplayerversion" value="8" ></param></mdo:flash><br></br> We recommend that you take your time over a game of matrix countdown and suggest two possible scoring systems:<br></br>  <br></br> <span style="font-weight: bold;">System 1:</span> Good scores get small values for the determinant of the difference between your answer and the target matrix.<br></br>  <br></br> <span style="font-weight: bold;">System 1:</span> Good scores get small values of the sum of the absolute values of the components of the difference between your answer and the target matrix.<br></br>  <br></br> These two systems allow for different strategies. Perhaps you might like to think about this?<br></br>  <br></br>  </p></mdoxml> 2 5 0 0 0 0 1 Play countdown with matrices Information and Communications Technology Interactivities Advanced Algebra Matrices