Rational or Irrational? That is the Question.

One of my favorite beginning of the year activities is a card sort that we do that reviews if different numbers are irrational or rational. Students are placed into groups of 4 and have to reason with one another about the placement of each number.

Here are a few groups placing their numbers:

Here are some example numbers we had:

Here are some finished products:

This was a great activity to get students use to classroom procedures and routines.  You can find the activity here: http://map.mathshell.org/lessons.php?unit=9105&collection=8&redir=1

The activity was in groups and went through each one large group.  I had students explain why they put them in certain categories and had a classroom discussion if they agreed or not.  Some could be put into more than one category depending on the explanation.  It was a fun experience.